Question 1

A tightrope walker walks across a 30.0 m long wire tied between two poles.The center of the wire is displaced vertically downward by 1.0 m when he is halfway across.If the tension in both halves of the wire at this point is 6294 N,what is the mass of the tightrope walker? Neglect the mass of the wire.

Accepted Answer

A) 85 kg 
B) 43 kg 
C) 74 kg 
D) 91 kg

Question 2

A stone rolls down a sloping hillside.The normal force that the surface of the hill exerts on the stone is equal to the stone's weight.

Accepted Answer

A) True 
 B)False

Question 3

Explain,from a force standpoint,how a rear spoiler on a race car helps keep the car on the road at high speeds.

Accepted Answer

The answer of Explain,from a force standpoint,how a rear spoiler...

Question 4

Two unequal masses M and m are connected by a light cord passing over a pulley of negligible mass.When released,the system accelerates.Friction is negligible.  Which figure below gives the correct free-body force diagrams for the two masses in the moving system?

Accepted Answer

A) 
 
B) 
 
C) 
 
D)

Question 5

You push downward on a trunk at an angle 25° below the horizontal with a force of 750 N.If the trunk is on a flat surface and the coefficient of static friction is 0.76,what is the most massive trunk you will be able to move? (Use g = 9.8 m/s2. )

Accepted Answer

A) 59 kg 
B) 68 kg 
C) 54 kg 
D) 82 kg

Question 6

A 615 N student standing on a scale in an elevator notices that the scale reads 645 N.From this information,the student knows that the elevator must be moving upward.

Accepted Answer

A) True 
 B)False

Question 7

A 10.0 kg block on a table is connected by a string to a 63 kg mass,which is hanging over the edge of the table.Assuming that frictional forces may be neglected,what is the magnitude of acceleration of the 10.0 kg block when the other block is released? (See the figure. )

Accepted Answer

A) 8.5 m/s2 
B) 8.1 m/s2 
C) 7.5 m/s2 
D) 9.0 m/s2

Question 8

Jason takes off across level water on his jet-powered skis.The combined mass of Jason and skis is 75 kg (the mass of the fuel is negligible).The skis have a thrust of 200 N and a coefficient of kinetic friction on water of 0.1.Unfortunately,the skis run out of fuel after only 90 s.What is Jason's top speed?

Accepted Answer

A) 150 m/s 
B) 240 m/s 
C) 24 m/s 
D) 90 m/s

Question 9

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 0.19,at what rate does the box accelerate down the slope? (Use g = 9.8 m/s2. )

Accepted Answer

A) 4.7 m/s2 
B) 5.2 m/s2 
C) 5.5 m/s2 
D) 6.2 m/s2

Question 10

A person with a mass of 78 kg is riding in an elevator that is accelerating upward at 1.80 m/s2.What is the person's apparent weight? (Use g = 9.8 m/s2. )

Accepted Answer

A) 900 N 
B) 760 N 
C) 620 N 
D) 960 N

Question 11

A 15,000 kg rocket blasts off from Earth with a uniform upward acceleration of 2.0 m/s2 and feels no air resistance.The thrust force its engines must provide during this acceleration is 30,000 N upward.

Accepted Answer

A) True 
 B)False

Question 12

The figure shows two 1.0 kg blocks connected by a rope.A second rope hangs beneath the lower block.Both ropes have a mass of 250 g.The entire assembly is accelerated upward at 2.3 m/s2 by force  .What is the tension at the top end of rope 1?

Accepted Answer

A) 18 N 
B) 15 N 
C) 2.9 N 
D) 3.5 N

Question 13

A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle.The coefficients of static and kinetic friction between the hockey puck and the metal ramp are µs = 0.40 and µk = 0.30,respectively.The puck's initial speed is 63 m/s.What vertical height does the puck reach above its starting point?

Accepted Answer

A) 130 cm 
B) 270 cm 
C) 200 cm 
D) 66 cm

Question 14

A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle.The coefficients of static and kinetic friction between the hockey puck and the metal ramp are µs = 0.40 and µk = 0.30,respectively.The puck's initial speed is 16 m/s.What vertical height does the puck reach above its starting point?

Accepted Answer

A) 8.6 cm 
B) 17 cm 
C) 13 cm 
D) 4.2 cm

Question 15

-In the figure,a 10 lb weight is suspended from two spring scales,each of which has negligible weight.Thus

Accepted Answer

A) each scale will read 5 lb. 
B) the top scale will read zero,the lower scale will read 10 lb. 
C) the lower scale will read zero,the top scale will read 10 lb. 
D) each scale will show a reading between one and 10 lb,such that the sum of the two is 10 lb.However,exact readings cannot be determined without more information. 
E) None of these is true.

Question 16

A driver in a 1000.0 kg car traveling at 24 m/s slams on the brakes and skids to a stop.If the coefficient of friction between the tires and the road is 0.80,how long will the skid marks be?

Accepted Answer

A) 37 m 
B) 30 m 
C) 46 m 
D) 34 m

Question 17

If you were to move into outer space far from any stars or planets,

Accepted Answer

A) your mass would change,but your weight would not change. 
B) your weight would change,but your mass would not change. 
C) both your weight and mass would change. 
D) neither your weight nor your mass would change. 
E) None of these is true.

Question 18

A fish is to be weighed at the harbor.If the mass of the fish is 69.0 kg,what will be the reading on the scale? (Use g = 9.8 m/s2. )

Accepted Answer

A) 676 N 
B) 7.04 N 
C) 7.74 N 
D) 744 N

Question 19

A 6.0 kg box is held at rest by two ropes that form 30° angles with the vertical.An external force F acts vertically downward on the box.The force exerted by each of the two ropes is denoted by T.A force diagram,showing the four forces that act on the box in equilibrium,is shown in the figure.The magnitude of force F is 410 N.The magnitude of force T is closest to:

Accepted Answer

A) 271 N 
B) 235 N 
C) 188 N 
D) 376 N 
E) 470 N

Exam 5: Applying Newtons Laws

A stone rolls down a sloping hillside.The normal force that the surface of the hill exerts on the stone is equal to the stone's weight.

Explain,from a force standpoint,how a rear spoiler on a race car helps keep the car on the road at high speeds.

Two unequal masses M and m are connected by a light cord passing over a pulley of negligible mass.When released,the system accelerates.Friction is negligible. Which figure below gives the correct free-body force diagrams for the two masses in the moving system?

You push downward on a trunk at an angle 25° below the horizontal with a force of 750 N.If the trunk is on a flat surface and the coefficient of static friction is 0.76,what is the most massive trunk you will be able to move? (Use g = 9.8 m/s². )

A 615 N student standing on a scale in an elevator notices that the scale reads 645 N.From this information,the student knows that the elevator must be moving upward.

A 10.0 kg block on a table is connected by a string to a 63 kg mass,which is hanging over the edge of the table.Assuming that frictional forces may be neglected,what is the magnitude of acceleration of the 10.0 kg block when the other block is released? (See the figure. )

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 0.19,at what rate does the box accelerate down the slope? (Use g = 9.8 m/s². )

A person with a mass of 78 kg is riding in an elevator that is accelerating upward at 1.80 m/s².What is the person's apparent weight? (Use g = 9.8 m/s². )

A 15,000 kg rocket blasts off from Earth with a uniform upward acceleration of 2.0 m/s2 and feels no air resistance.The thrust force its engines must provide during this acceleration is 30,000 N upward.

The figure shows two 1.0 kg blocks connected by a rope.A second rope hangs beneath the lower block.Both ropes have a mass of 250 g.The entire assembly is accelerated upward at 2.3 m/s² by force .What is the tension at the top end of rope 1?

-In the figure,a 10 lb weight is suspended from two spring scales,each of which has negligible weight.Thus

A driver in a 1000.0 kg car traveling at 24 m/s slams on the brakes and skids to a stop.If the coefficient of friction between the tires and the road is 0.80,how long will the skid marks be?

If you were to move into outer space far from any stars or planets,

A fish is to be weighed at the harbor.If the mass of the fish is 69.0 kg,what will be the reading on the scale? (Use g = 9.8 m/s². )