Question 1

In the figure,what does the spring scale read? The pulleys are ideal and the strings and scale are also massless.

Accepted Answer

A) exactly 2.0 N. 
B) exactly 1.0 N 
C) 0.50 N 
D) 0.00 N 
E) more than 19.6 N 
A) exactly 2.0 N. 
B) exactly 1.0 N 
C) 0.50 N 
D) 0.00 N 
E) more than 19.6 N

Question 2

A 1000-kg barge is being towed by means of two horizontal cables.One cable is exerting a force of 80.0 N in a direction 30.0° west of north.In what direction should the second cable pull so that the barge will accelerate northward,if the force exerted by the cable is 120 N? Assume that the water exerts no appreciable frictional drag on the barge.

Accepted Answer

A) 19.5° east of north 
B) 21.1° east of north 
C) 39.0° east of north 
D) 47.5° east of north 
E) 54.7° east of north 
A) 19.5° east of north 
B) 21.1° east of north 
C) 39.0° east of north 
D) 47.5° east of north 
E) 54.7° east of north

Question 3

Two boxes P and Q on a perfectly smooth horizontal surface are connected by a light horizontal cord.The mass of P is greater than that of Q.A horizontal force $\overrightarrow { \mathrm { F } }$ is exerted on box Q as shown in the figure,accelerating the bodies to the right.The magnitude of the force exerted by the connecting cord on body P is

Accepted Answer

A) zero. 
B) less than F but not zero. 
C) equal to F. 
D) greater than F. 
A) zero. 
B) less than F but not zero. 
C) equal to F. 
D) greater than F.

Question 4

A flatbed truck is carrying a 20-kg crate up a sloping road.The coefficient of static friction between the crate and the bed is 0.40,and the coefficient of kinetic friction is 0.30.What is the maximum angle of slope that the truck can climb at constant speed if the crate is to stay in place?

Accepted Answer

A) 0.38° 
B) 13° 
C) 17° 
D) 22° 
E) 68° 
A) 0.38° 
B) 13° 
C) 17° 
D) 22° 
E) 68°

Question 5

A football kicker is attempting a field goal from $44 \mathrm {~m}$ out.The ball is kicked and just clears the lower bar with a time of flight of $2.9 \mathrm {~s}$ If the angle of the kick was 45°,what was the initial speed of the ball,assuming no effects of air?

Accepted Answer

A) 21.5 m/s 
B) 19.7 m/s 
C) 2.2 m/s 
D) 39 m/s 
A) 21.5 m/s 
B) 19.7 m/s 
C) 2.2 m/s 
D) 39 m/s

Question 6

A 958-N rocket is coming in for a vertical landing.It starts with a downward speed of 25 m/s and must reduce its speed to 0 m/s in 8.0 s for the final landing.
(a)During this landing maneuver,what must be the thrust force exerted on the rocket by the expelled gas??
(b)What must be the direction of the engine thrust force?

Accepted Answer

(a)1300 N

Question 7

A shell is launched with a velocity of 100 m/s at an angle of 30.0° above horizontal from a point on a cliff 50.0 m above a level plain below.How far from the base of the cliff does the shell strike the ground? There are no appreciable effects of air,and g = 9.80 m/s2 at the location of the cliff.

Accepted Answer

Question 8

A system consisting of blocks,a light frictionless pulley,a frictionless incline,and very light connecting wires is shown in the figure.The wires pull on the left-hand blocks parallel to the surface of the ramp.The 9.0-kg block accelerates downward when the system is released gently from rest.
(a)What is the magnitude of the acceleration of the 9.0-kg block?
(b)What is the tension force that the wire connecting the two blocks on the incline exerts on the blocks?

Accepted Answer

The answer of A system consisting of blocks,a light frictionless...

Question 9

A projectile is launched with an initial velocity of 80 m/s at 30° above the horizontal.Neglecting air,what is horizontal component of the projectile's acceleration?

Accepted Answer

A) 80 m/s2 
B) 40 m/s2 
C) 9.8 m/s2 
D) 0 m/s2 
E) 69 m/s2 
A) 80 m/s2 
B) 40 m/s2 
C) 9.8 m/s2 
D) 0 m/s2 
E) 69 m/s2

Question 10

In an air-free chamber,a pebble is thrown horizontally,and at the same instant a second pebble is dropped from the same height.Compare the times of fall of the two pebbles.

Accepted Answer

A) The thrown pebble hits first. 
B) The dropped pebble hits first. 
C) They hit at the same time. 
D) We cannot tell without knowing which pebble is heavier. 
A) The thrown pebble hits first. 
B) The dropped pebble hits first. 
C) They hit at the same time. 
D) We cannot tell without knowing which pebble is heavier.

Question 11

A projectile is thrown upward at 24° with the vertical and returns to the horizontal ground 12.5 s later.Assume no air effects.
(a)How fast was it thrown?
(b)How far from its original position did it land?
(c)How high above its original position did it go?

Accepted Answer

(a)67 m/s

Question 12

A car of mass 1100 kg that is traveling at 27 m/s starts to slow down and comes to a complete stop in 578 m.What is the magnitude of the average stopping force exerted on the car?

Accepted Answer

A) 690 N 
B) 550 N 
C) 410 N 
D) 340 N 
A) 690 N 
B) 550 N 
C) 410 N 
D) 340 N

Question 13

Three forces are exerted on an object and as a result the object moves with a constant velocity.One force is 60 N along the +x-axis,the second is 75 N along a direction making a counterclockwise angle of 150° with the +x-axis.
(a)What is the magnitude of the third force?
(b)What is the direction of the third force,measured clockwise from the +x-axis?

Accepted Answer

The answer of Three forces are exerted on an object...

Question 14

A projectile is fired from the edge of a cliff as shown in the figure.The initial velocity components are 940 m/s (horizontal)and 96 m/s (vertical).The projectile reaches maximum height at point P and then falls and strikes the ground at point Q.How high is point P above point Q,assuming no air effects?

Accepted Answer

A) 470 m 
B) 490 m 
C) 45,000 m 
D) 940 m 
E) 90,000 m 
A) 470 m 
B) 490 m 
C) 45,000 m 
D) 940 m 
E) 90,000 m

Question 15

The magnitude of a vector an only zero if all of its components are zero.

Accepted Answer

A) True 
 B)False

Question 16

A 2.8-kg tool can move on a perfectly smooth ramp that slants at 42° above the horizontal.What are the magnitude and direction of the acceleration of this tool if it is sliding (a)up the ram,(b)down the ramp?

Accepted Answer

(a)6.6 m/s² down the

Question 17

A ball thrown horizontally from a point 24 m above the ground,strikes the ground after traveling horizontally a distance of 18 m.With what speed was it thrown,assuming negligible air effects?

Accepted Answer

A) 6.1 m/s 
B) 7.4 m/s 
C) 8.1 m/s 
D) 8.9 m/s 
A) 6.1 m/s 
B) 7.4 m/s 
C) 8.1 m/s 
D) 8.9 m/s

Question 18

A 6.0-kg box slides down an inclined plane that makes an angle of 39° with the horizontal.If the coefficient of kinetic friction is 0.40,at what rate does the box accelerate down the slope?

Accepted Answer

A) 3.1 m/s2 
B) 3.4 m/s2 
C) 3.7 m/s2 
D) 4.1 m/s2 
A) 3.1 m/s2 
B) 3.4 m/s2 
C) 3.7 m/s2 
D) 4.1 m/s2

Question 19

The x component of vector $\vec { A }$ is 8.7 units,and its y component is -6.5 units.The magnitude of $\vec { A }$ is closest to

Accepted Answer

A) 9.9 units 
B) 7.9 units 
C) 8.9 units 
D) 11 units 
E) 12 units 
A) 9.9 units 
B) 7.9 units 
C) 8.9 units 
D) 11 units 
E) 12 units

Question 20

A rock is thrown from the roof of a building,with an initial velocity of 10 m/s at an angle of 30° above the horizontal.The rock is observed to strike the ground 43 m from the base of the building.What is the height of the building assuming no air?

Accepted Answer

The answer of A rock is thrown from the roof...

Exam 4: Applying Newtons Laws

In the figure,what does the spring scale read? The pulleys are ideal and the strings and scale are also massless.

A flatbed truck is carrying a 20-kg crate up a sloping road.The coefficient of static friction between the crate and the bed is 0.40,and the coefficient of kinetic friction is 0.30.What is the maximum angle of slope that the truck can climb at constant speed if the crate is to stay in place?

A football kicker is attempting a field goal from 44 m44 \mathrm {~m}44 m out.The ball is kicked and just clears the lower bar with a time of flight of 2.9 s2.9 \mathrm {~s}2.9 s If the angle of the kick was 45°,what was the initial speed of the ball,assuming no effects of air?

A shell is launched with a velocity of 100 m/s at an angle of 30.0° above horizontal from a point on a cliff 50.0 m above a level plain below.How far from the base of the cliff does the shell strike the ground? There are no appreciable effects of air,and g = 9.80 m/s2 at the location of the cliff.

A projectile is launched with an initial velocity of 80 m/s at 30° above the horizontal.Neglecting air,what is horizontal component of the projectile's acceleration?

In an air-free chamber,a pebble is thrown horizontally,and at the same instant a second pebble is dropped from the same height.Compare the times of fall of the two pebbles.

A projectile is thrown upward at 24° with the vertical and returns to the horizontal ground 12.5 s later.Assume no air effects. (a)How fast was it thrown? (b)How far from its original position did it land? (c)How high above its original position did it go?

A car of mass 1100 kg that is traveling at 27 m/s starts to slow down and comes to a complete stop in 578 m.What is the magnitude of the average stopping force exerted on the car?

The magnitude of a vector an only zero if all of its components are zero.

A 2.8-kg tool can move on a perfectly smooth ramp that slants at 42° above the horizontal.What are the magnitude and direction of the acceleration of this tool if it is sliding (a)up the ram,(b)down the ramp?

A ball thrown horizontally from a point 24 m above the ground,strikes the ground after traveling horizontally a distance of 18 m.With what speed was it thrown,assuming negligible air effects?

A 6.0-kg box slides down an inclined plane that makes an angle of 39° with the horizontal.If the coefficient of kinetic friction is 0.40,at what rate does the box accelerate down the slope?

The x component of vector A⃗\vec { A }A is 8.7 units,and its y component is -6.5 units.The magnitude of A⃗\vec { A }A is closest to

A rock is thrown from the roof of a building,with an initial velocity of 10 m/s at an angle of 30° above the horizontal.The rock is observed to strike the ground 43 m from the base of the building.What is the height of the building assuming no air?

Introduction

Kinematics: Motion in One Dimension

Newtonian Mechanics

Circular Motion

Impulse and Linear Momentum

Work and Energy

Extended Bodies at Rest

Rotational Motion

Gases

Static Fluids

Fluids in Motion

First Law of Thermodynamics

Second Law of Thermodynamics

Electric Charge force and Energy

The Electric Field

Dc Circuits

Magnetism

Electromagnetic Induction

Vibrational Motion

Mechanical Waves

Reflection and Refraction

Mirrors and Lenses

Wave Optics

Electromagnetic Waves

Special Relativity

Quantum Optics

Atomic Physics

Nuclear Physics

Particle Physics

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A football kicker is attempting a field goal from $44 \mathrm {~m}$ out.The ball is kicked and just clears the lower bar with a time of flight of $2.9 \mathrm {~s}$ If the angle of the kick was 45°,what was the initial speed of the ball,assuming no effects of air?

The x component of vector $\vec { A }$ is 8.7 units,and its y component is -6.5 units.The magnitude of $\vec { A }$ is closest to