Read the following very carefully and use the advice, videos, and formulas we have given in order to review. Good Luck!(Some problems require the use of formulas from a different unit). 5 multiple choice and 1 free response.
1. A 1,500 kg car has an initial speed of 15 meters per second. The driver applies the brakes, and the car stops in 8.1 seconds. What is the magnitude of the braking force?
A. 19,000 N
B. 30,000 N
C. 14,000 N
D. 21,000 N
2. A 150kg box is initially at rest when a student uses arope to pull on it with 650 N of force for 2.0 seconds. Friction is negligible. What is the best estimate of the speed?
A. 7.0 m/s
B. 8.6 m/s
C. 8.2 m/s
D. 9.5 m/s
3. An ambulance driver accelerates from rest to 14 meters per second in 2.5 seconds. The magnitude of the force of friction is 9,500 N. What is the best estimate of the mass of the ambulance?
A. 9,500 kg
B. 3,400 kg
C. 1,700 kg
D. 2,500 kg
4. A 52 gram box is initially at rest when a student pushes it with a force of 280 N for 2.5 meters. Friction is negligible. What is the best estimate of the speed?
A. 4.0 m/s
B. 5.2 m/s
C. 6.7 m/s
D. 3.3 m/s
5. A police car accelerates from rest to 16 m/s over a distance of 21 meters. The magnitude of the force of friction is 8,700N. What is the best estimate of the mass?
A. 2,800 kg
B. 1,400 kg
C. 1,800 kg
D. 1,200 kg
6. A astronaut on a moon with no atmosphere is studying gravity. She drops the ball off a 3.o meter high cliff. The ball hits the ground in 1.5 seconds. The magnitude of the gravitational force is 5.0 N. What is the best estimate of the mass of the ball?
1. A 1,500 kg car has an initial speed of 15 meters per second. The driver applies the brakes, and the car stops in 8.1 seconds. What is the magnitude of the braking force?
A. 19,000 N
B. 30,000 N
C. 14,000 N
D. 21,000 N
2. A 150kg box is initially at rest when a student uses arope to pull on it with 650 N of force for 2.0 seconds. Friction is negligible. What is the best estimate of the speed?
A. 7.0 m/s
B. 8.6 m/s
C. 8.2 m/s
D. 9.5 m/s
3. An ambulance driver accelerates from rest to 14 meters per second in 2.5 seconds. The magnitude of the force of friction is 9,500 N. What is the best estimate of the mass of the ambulance?
A. 9,500 kg
B. 3,400 kg
C. 1,700 kg
D. 2,500 kg
4. A 52 gram box is initially at rest when a student pushes it with a force of 280 N for 2.5 meters. Friction is negligible. What is the best estimate of the speed?
A. 4.0 m/s
B. 5.2 m/s
C. 6.7 m/s
D. 3.3 m/s
5. A police car accelerates from rest to 16 m/s over a distance of 21 meters. The magnitude of the force of friction is 8,700N. What is the best estimate of the mass?
A. 2,800 kg
B. 1,400 kg
C. 1,800 kg
D. 1,200 kg
6. A astronaut on a moon with no atmosphere is studying gravity. She drops the ball off a 3.o meter high cliff. The ball hits the ground in 1.5 seconds. The magnitude of the gravitational force is 5.0 N. What is the best estimate of the mass of the ball?
Solutions
1. D.
2. B.
3. C.
4. B.
5. B.
6. y=v0t+1/2at^2
a=2(deltay-v0t)/2
=2(-3.0m-(1.5)/1.5^2
=-2.7 m/s
m=Fg/a
=-5.0/-2.7
=1.9 kg
2. B.
3. C.
4. B.
5. B.
6. y=v0t+1/2at^2
a=2(deltay-v0t)/2
=2(-3.0m-(1.5)/1.5^2
=-2.7 m/s
m=Fg/a
=-5.0/-2.7
=1.9 kg