Exam 4: Applying Newtons Laws

A 200-g hockey puck is launched at an initial speed of 16 m/s 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 µ_s = 0.40 and µ_k = 0.30,respectively.What vertical height does the puck reach above its starting point?

James and John dive from an overhang into the lake below.James simply drops straight down from the edge.John takes a running start and jumps with an initial horizontal velocity of 25 m/s.Assuming no effects of air,when they reach the lake below

A 50.0-kg crate is being pulled along a horizontal smooth surface.The pulling force is 10.0 N and is directed 20.0° above the horizontal.What is the magnitude of the acceleration of the crate?

If a vector $\vec { A }$ has components A_x > 0,and A_y < 0,then the angle that this vector makes with the positive x-axis must be in the range

A driver in a $1000 - \mathrm { kg }$ car traveling at $24 \mathrm {~m} / \mathrm { s }$ slams on the brakes and skids to a stop.If the coefficient of friction between the tires and the level road is 0.80,how long will the skid marks be?

For general projectile motion if we neglect air,the horizontal component of a projectile's velocity

A batter hits a home run in which the ball travels 110 m horizontally with no appreciable effects of air.If the ball left the bat at 50° above the horizontal just above ground level,how fast was it hit?

Which of the following statements are true about an object in two-dimensional projectile motion if we neglect air? (There could be more than one correct choice.)

Enzo throws a rock horizontally with a speed of 12 m/s from a bridge.It falls for 2.28 s before reaching the water below.Ignore air.Just as the rock reaches the water,find (a)the horizontal component of its velocity. (b)the speed with which it is moving.

A locomotive is pulling 9 freight cars,each of which is loaded with the same amount of mass.The mass of each loaded car is $37,000 \mathrm {~kg} \text {, }$ and we can neglect friction forces exerted on these 9 cars.If the train is accelerating forward at $0.81 \mathrm {~m} / \mathrm { s } ^ { 2 }$ on a level track,what is the tension force that the coupling between the second and third cars exerts on them? (The car nearest the locomotive is counted as the first car.)

As shown in the figure,a heavy rock is shot upward from the edge of a vertical cliff.It leaves the edge of the cliff with an initial velocity of 15 m/s directed at 25° from the vertical.Assume that air has no effect on the motion of the rock.How high is the cliff?

Mary and Debra stand on a snow-covered roof.They both throw snowballs with the same initial speed,but in different directions.Mary throws her snowball downward,at 30° below the horizontal; Debra throws her snowball upward,at 30° above the horizontal.Which of the following statements are true about just as the snowballs reach the ground below? Neglect the effects of air.(There could be more than one correct choice.)

A projectile is fired from ground level with a speed of 150 m/s at an angle 30° above the horizontal on an airless planet where g = 10.0 m/s².What is the horizontal component of its velocity after 4.0 s?

The magnitude of $\vec { A }$ is 5.5 m,and this vector lies in the second quadrant and makes an angle of 34 ° with the +y-axis.The components of $\vec { A }$ are closest to:

A bulldozer attempts to drag a log weighing 500 N along the rough horizontal ground.The cable attached to the log makes an angle of 30° above the ground.The coefficient of static friction between the log and the ground is 0.50,and the coefficient of kinetic friction is 0.35.What minimum force should the cable exert on the log tension in order for the log to begin to slide?

A boy jumps with a velocity of magnitude 20.0 m/s at an angle of 25.0° above the horizontal.What is the horizontal component of the boy's velocity?

An athlete competing in the long jump leaves the ground with a speed of 9.14 m/s at an angle of 35° above the horizontal.How long does the athlete stay in the air,assuming no effects of air?

A 5.0-kg stone is thrown upward at 7.5 m/s at an angle of 51° above the horizontal from the upper edge of a cliff,and it hits the ground 1.5 s later.Neglect air.Find the magnitude of its velocity vector just as it reaches the ground.

A 3.0-kg object and a 5.0-kg object hang vertically at the opposite ends of a very light rope that goes over an ideal pulley.If the objects are gently released,what is the resulting acceleration of the objects?

A projectile is shot horizontally at 23.4 m/s from the roof of a building 55 m tall. Effects of air are negligible. (a)Determine the time necessary for the projectile to reach the ground below. (b)Determine the distance from the base of the building that the projectile lands. (c)Determine the horizontal and vertical components of the velocity just before the projectile reaches the ground.