Physics

How long will it take a flower pot to fall on the sidewalk if it is thrown down from a 15m building with an initial speed of 28m/s?

-.49

A 75kg person traveling at a constant velocity on ice skates experiences a force of -40 N. What is the person's acceleration?

-.53m/s2

A golf ball of mass .05kg acquires a speed of 80m/s when hit with a force of 3000N. How long was the club in contact with the ball?

.0013

If 50 N of force are needed to slide an object with a mass of 150kg, what is the coefficient of friction between the object and floor?

.03

A 65 kg ice skater traveling at 6m/s runs head on into an 85kg skater traveling straight forward at 4.5m/s. At what speed and in what direction do the ice skaters travel if they move together after the collision?

.05m/s

a 62kg child is sitting on a wag full of bricks that has a mass of 150kg. In order to move the wagon without touching the ground, the child throws two bricks each of mass 3kg in the direction opposite to the direction the wagon is to go. How fast will the wagon move if the ricks are thrown at 2m/s?

.06m/s

A ball with a mass of 20 g moving at 15 m/s collides with a second ball of mass 36 g moving at 5m/s. AFter the collision the 20g ball moves at 6m/a. What is the change in momentum of the 36g ball?

.18

An object of mass 70kg is accelerated by a force of 20N. What is its acceleration?

.29ms/2

a 2500 kg car is traveling at a constant speed of 14m/s along an icy, but straight and level, road. The drive of the car, seeing an approaching traffic light turn red, slams on the brakes. Wheels locked and tires skidding, the car slides to a halt in a distance of 25 m. What is the coefficient of sliding friction between tires and icy roadbed?

.392

A brick has mass of 1.2kg. A force of 5.4N is needed to move the brick along the floor with a constant velocity. What is the coefficient of friction?

.45

What impulse is needed to stop a 45g mass traveling at 10 m/s?

.45kg

A coin is flicked form a 1.7m table and lands 3.2m away from it. How long was the coin in the air?

.59s

A man that weighs 950N steps from a boat that has a mass of 40kg. If the acceleration of the boat away from the dock is 1.5m/s2, what is the man's acceleration?

.63m/s2

How much energy is stored in a spring with a spring constant of 200N/m that is compressed 8cm?

.64J

A force of 540N is used to stop an object with a mass of 5kg moving 175 m/s. Hw long will it take to bring the object to a full stop?

1.62s

How long will it take the same pot to fall if it is just dropped from 15m?

1.74

What impulse is needed to stop a 45g mass traveling at 42 m/s?

1.89kg(m/s)

If a horizontal force of 30N is required to slide a 12kg wooded crate across the floor at a constant velocity, what is the coefficient of sliding friction between crate and floor?

1/4

Object A has a momentum of 60N. Object B, which has the same mass, is standing motionless. Object A strikes object B and stops. IF the mass of object B is 6kg, the velocity of object B after the collision is...

10m/s

An 85kg person is accelerated at 3m/s2 upward by an elevator. What force would be measured if the person was standing on the scale?

1105N

A race car was accelerating at a rate of 1.7m/s2 from a velocity of 25m/s to 32m/s. What was the car displacement during this time?

117.35m

How much work is done when a machine runs at 500-W for 4 minutes?

120,000J

How much power does it requires to load four 50kg boxes onto a 1.2 m loading dock in 2 seconds?

1200W

How far did a girl drive is she used brakes and slowed from from 26m/s to rest with an acceleration -5.7m/s2? How much will the total stopping distance increase if she waits .5s to hit the breaks?

13m more, 72.3m in total

A ball acquires a speed of 12m/s when a force is applied for a distance of .5m. If the ball has a mass of 1kg, what is the force applied?

144N

A soccer ball is kicked form the corner and lands at the goal 20 m away. If it needs to clear the 2m high defenders standing half way in between with what speed and angle does it need to be kicked?

16.9m/s, 21.8 degrees

A fullback of mass 120 kg traveling at 20m/s collides with another player and comes to rest in 1.5 s. What was the force of the impact?

1600N

What is the weight of a boulder that has a mass of 17kg?

170N

A water balloon is launched and i is determined that it is in the air for 2.4 seconds and lands 30m away. What was the launch speed of the balloon and at what angle was it launched?

17m/s, 43 degrees

The coefficient of starting friction for wood on wood is .55. What is the force of friction of wood block of mass 3.5kg being pulled on a wood floor?

19.25N

A snowball with a mass of 90g hits a snowman's top hat and sticks to it. The hat and the snowball, with a combined mass of 220g, fall off together at 8m/s. How fast was the snowball moving at the moment of impact?

19.5m/s

In a lab with a car, pulley and hanging weight. A 1.5kg car is accelerated by a falling mass of .5kg. If friction is not significant, what is the acceleration?

2.5m/s2

A car has an initial velocity of 17m/s. How long does this car need to accelerate at 5.3m/s2 to reach a velocity of 32 m/s?

2.83s

A force of 540N is used to stop an object with a mass of 65kg moving at 175m/s. How long will it take to bring the object to a full stop?

21.06s

A speedboat has a mass of 500kg. It starts from rest and travels 200 m in 3s. THe boat undergoes uniform acceleration during the 3s. What is the unbalanced force on the boat?

22,220N

How much work is done when a 70kg runner accelerates form rest to 8m/s

2240J

Calculate the gravitational energy of a 20kg boy at the top of a 12m hill

2400J

What force would be needed to accelerate a stone that weighs 20N in an upward direction at 2.5m/s2?

25N

A 60kg boy and a 40kg girl engage in a tug of war on an icy frictionless surface. If the acceleration of the girl toward the boy is 3m/s2. determine the magnitude of the acceleration of the boy toward the girl.

2m/s2

What is the acceleration of a 500N box if it is being pulled along a horizontal surface (u=.4) by a rope held parallel to the surface? The tension in the rope is 300N.

2m/s2

A paper football is flicked form a table top and lands on the table 70cm away. If it was in the air for .24s, what was the speed of the paper football left the finger and at what angle was it launched?

3.1m/s, 22 degrees

A car with a mass of 1500kg changes its speed form 10m/s to 30m/s during a 10s interval. Calculate the net average force acting on the car during the 10s interval.

3000N

A 10,000kg freight car is rolling along a track at 3m/s. Calculate the time needed for a force of 1000N to stop the car.

30s

A mortar shell is launched with a speed of 175m/s. If it is launched at a 45 degree angle how high of an obstacle can it go over and far away can it hit a target?

3122m, 780m

In hitting a stationary hockey puck having mass of 180g, a hockey player gives the puck an impulse of 6s. At what speed will the puck move toward the goal?

33.3m/s

A boulder of mass 45 kg is pushed on a surface with a coefficient of sliding friction of .85. What force has to be applied to produce an acceleration with .2m/s2?

391.5N

Starting from rest, a car undergoes a constant acceleration of 6m/s2. How far will the car travel in the first second?

3m

What is the greatest upward acceleration a 70kg boy climbing a rope can attain without breaking the rope if the rope can support 1000N?

4.3m/s2

Calculate the kinetic energy of a 5 kg dog running at 4m/s

40J

A ball is thrown horizontally from the top of a tall cliff. What vertical distance does the ball fall in 3 seconds?

44.1m

How much does the internal energy change when a 10kg box slides along a floor providing a 120 N friction force for 4m?

480J

How much energy is gained by a 5g paint pellet in a paint ball gun if a 1200N force is exerted on it along the 40cm barrel?

480J

A bank robber needs to thrown his ill-gotten booty over the fence before climbing it. If the fence is 3m high and the package lands 1 m away, how fast and at what angle should the thief throw his package?

5.5m/s, 53 degrees

If a 54N impulse is given to a 6kg object, the change of momentum for the object is...

54N

Lucy noticed road construction. How far did she drive if she used brakes and slowed down from 26m/s to rest with an acceleration of -5.7m/s2?

59.29m

What is the mass of an object that is accelerated at 25m/s2 by a force of 125N?

5kg

A metal sphere with a mass of 50g rolls along a frictionless surface at 20m/s and strikes a stationary sphere having a mass of 200g. The first sphere stops completely. At what speed does the second sphere move away from the point of impact?

5m/s

A 10kg mass on a frictionless table is accelerated by a 5 kg mass hanging from the table below. Calculate the acceleration of the mass on the table

5m/s2

A man wants to escape from a burning building by sliding down a rope which can only support 400N. If the man weighs 800N, what is the smallest acceleration he can have and not break the rope?

5m/s2

How much time does a car with an acceleration of 4 m/s2 take to go from 10 m/s to 30 m/s?

5s

A skier is coasting on perfectly smooth snow at 7m/s and crosses a rough patch of snow 35m long. If the frictional force exerted on the skier is 6N, what is her speed as she leaves the patch of snow? Assume the skier and her skis have a mass of 90kg

6.8m/s

A jumbo jet requires 32 seconds to reach a stop when landing at a speed of 40m/s. If its mass is 50,000kg, what is the average breaking force?

62,500N

Calculate the total energy of a 100kg bike rider at the top of a 6m hill moving at 3m/s

6450J

In hitting a stationary hockey puck having a mass of 90g, a hockey player gives the puck an impulse of 6Ns. At what speed will the puck move toward the goal?

66.7m/s

What force acting for .00135, wil change the velocity of a 95g baseball from 50m/s eastward to 45m/s westward?

6685N

A student has a mass of 68kg. What is the student's weight?

680N

A stone weighs 5.4N. What force must be applied to make it accelerate upward at 3m/s2?

7.02N

A stone weights 5.4 N. What force must be applied to make it accelerate upward at 3m/s2?

7.02N

A white eagle is flying 12 m/s on 250m height. He drops a baby rabbit. How long will it take the rabbit to hit the ground?

7.14s

A projectile is launched from the ground at 35m/s at 20 degree angle. How high does the projectile reach and how far away does it land?

7.35m, 80.5m

a 70kg astronaut is standing on a scale in a spaceship as shown below. While the ship is moving in a straight line with a constant velocity of 100 m/s ear a large planet, the scale reads 300N. The ship then accelerates away from the planet at 7m/s2 in the direction indicated. What does the scale read now?

790N

Calculate the speed of a 100kg biker at the top of a 5 m hill moving at 3 m/s if she coasts down to a 3 m height

8.3m/s

A 4kg object traveling westward at 25m/s hits a 15kg object at rest. The 5kg object bounces eastward at 8m/s. What is the speed and direction of the 15kg object?

8.8m/s

A bullet of mass .65kg is fired form a 4kg gun with a speed of 500m/s. What is the recoil velocity of the gun?

81.25m/s

A bicyclist and his bicycle have a mass of 105kg. What force is necessary to bring him to rest when he is traveling at 25m/s and must stop to avoid a tree 4m in front of him?

8203.125N

An eagle is flying 12 m/s on 250m height. He drops a baby rabbit. How far will the rabbit travel horizontally before hitting the ground?

85.7m

A metal sphere with a mass of 80g rolls along a frictionless surface at 20m/s and strikes a stationary sphere having a mass of 200g. The first sphere stops completely. At what speed does the second sphere move away from the point of impact.

8m/s

A 24 kg dog running at a speed of 3m/s jumps onto a stationary skateboard that has a mass of 3.6kg. How long will it take an average force of 9N to stop the skateboard and dog?

8s

A mass of 56kg has a weight of 504 N on top of a mountain. What is the value of g?

9m/s2

An 180g baseball is thrown at 30m/s toward a batter who strikes it so that the ball leaves the bat at 45 m/s in the opposite direction? If the bat and ball are in contact for .002s, what is the force of the ball bat on the ball? And what is the force of the ball on the bat?

a. 6750N b. the same

A certain force F gives a mass M an acceleration of a. Therefore, force F will give a mass of 2M an acceleration of

a/2

Which has the greater momentum: a 145g baseball traveling at 40m/s of a 45g golf ball traveling at 67m/s. How much greater?

baseball, 5.8kg(m/s)