Momentum
If a train is moving East with a momentum of 4,000,000 kg*m/s but is only traveling at 20 m/s, what is its mass?
200000 kg
You serve a volleyball with a mass of 2.1 kg. The ball leaves your hand with a speed of 30 m/s. How much kinetic energy does the ball have?
945 J
At hockey tryouts, a senior (mass = 60 kg) moving at a velocity of 3 m/s slams into a sixie (mass = 30 kg) who is stationary. If their laces get tangled and they are stuck together, what will their combined velocity be as they skid across the ice?
2 m/s
If a small motor does 520 J of work to move a toy car 260 m, what force does it exert?
If it does this over the course of 0.4 seconds, what power is required?
2 Newtons
5 Watts
If a 680 watt lightbulb is running for 2.5 seconds, how much work does it do?
1700 Joules
A 2kg cat is initially walking forwards at 1.1 m/s and accelerates to 4.2 m/s. What is the change in the cat's momentum during this time period?
6.2 N*s
A bowling ball (mass = 7 kg) is moving at a velocity of 12 m/s. How high would you have to lift this bowling ball to give it the same amount of PE as it has KE?
7.3 m
A grocery shopper tosses a 2 kg bottle of laundry detergent into a stationary 15 kg grocery cart. The bottle is moving with a horizontal velocity of 6 meters per second before it hits the cart. At what velocity will the cart (with detergent now in it) move forward?
0.705 m/s
A bullet (mass = 0.1 kg) initially traveling at 90 m/s gets fired into a tree, and it comes to a stop after piercing 0.6 meters into the trunk of the tree. What force did the tree apply to stop the bullet?
(-) 675 N
A boxer is trying to increase the impulse delivered by his punches. At first, he can punch with a force of 96 N and he makes contact for 1.4 seconds. If he speeds up and delivers the same force but only makes contact for 0.6 seconds, how much more impulse is he delivering?
76.8 N*s
A bicycle has a momentum of 24 kg*m/s. What momentum would it have if the mass of the bike were tripled and the velocity were halved?
36 kg*m/s
A baseball player says he can hit a 1.2 kg ball so hard that it will fly away with a velocity of 30 m/s. A golfer thinks he is just as strong, and can give a golf ball just as much KE. How fast does the golf ball (0.4 kg) need to be moving to have the same KE as the baseball?
51.96 m/s
A fisherman drags a net (mass = 6 kg) through the water with a velocity of 4 m/s. A fish, who is traveling 2 m/s the other direction and has a mass of 5 kg, gets caught in the net. Assuming the fish remains tangled in the net, what will be the velocity of the net be as it continues forward?
1.27 kg
Michael pushes a lawnmower across the grass with a force of 182 N. If doing so over the course of 3 seconds requires 900 Watts of power, what distance is Michael pushing the mower?
14.83 M
A 23 kg canoe moving to the right at 12 m/s makes an elastic collision with a 4 kg raft moving to the left at 5 m/s. After the collision, the canoe is stationary. How fast will the raft move away?
64 m/s
A bowling ball falling downwards at - 8 m/s initially has a momentum of -56 N*s. If it bounces up and begins going 4 m/s upwards, what was its change in momentum?
84 N*s
If a 60 kg student is wearing a 2 kg helmet and riding on a 14 kg skateboard moving at 13 m/s, what is the total kinetic energy of the system?
6422 J
A 26 kg student runs down the sidewalk and jumps with a horizontal speed of 3 m/s onto a longboard that is moving at 1 m/s. The student and the longboard move down the sidewalk together with a speed of 2.5 m/s. What is the mass of the longboard?
8.67 kg
A 30 kg child is dangling off a roof 12 m above the ground. If he falls, and all of his PE gets converted to KE, how fast will he be moving just before it hits the ground?
If he falls onto a trampoline, which can provide a force of 900 N to help bring him to a stop, how far (what distance) will the trampoline stretch to cushion his fall?
V = 15.33 m/s
D = 3.92 m
A 600 kg truck is moving at a velocity of 10 m/s when suddenly the driver sees a puppy ahead in the road. If they slam on the brakes and stops in 3.2 seconds, how much force did the brakes apply to stop the car?
1875 N
During a football game, a Belmont Hill receiver (mass = 50 kg) is running down the field at + 4 m/s and an RL linebacker hits him so hard that he flies backwards. If his change in momentum is -400 N*s, what is his final backwards velocity?
-4 m/s
During a perfectly elastic collision, kinetic energy is conserved. Before the crash, a 100 kg car moves at 5 m/s and hits a 40 kg skateboarder. After the crash, the car moves at 2.14 m/s. What must be the new velocity of the skateboarder, and what is the total kinetic energy of the system?
V = 7.15 m/s
KE = 1250 J
A 40 kg skier moving at 6 m/s collides with a smaller skier who was going 3 m/s. After the collision, the larger guy continues at 2 m/s, and the smaller skier speeds off at 9.4 m/s. What is the smaller skier's mass?
25 kg
A 14 N force acts on a 0.6 kg tennis ball and accelerates it from rest to 12 m/s. How long (over what distance) was the force acting?
3.08 M
For how long a time must a tow truck pull with a force of 550 N on a stalled 1200 kg car to give it a forward velocity of 2.0 m/s?
4.36 seconds