- #1

- 57

- 0

1. A 14 kg bucket of water is raised from a well by a rope. If the upward acceleration of the bucket is 2.2 m/s2, find the force exerted by the rope on the bucket of water.

in Newtons

2. A boat moves through the water with two forces acting on it. One is a 6.5 103 N forward push by the motor, and the other is a 0.9 103 N resistive force due to the water.

(a) What is the acceleration of the 1200 kg boat?

m/s2

(b) If it starts from rest, how far will it move in 9 s? in

m

(c) What will its velocity be at the end of this time interval? in

m/s

3. [SFHS99 4.P.27.] A 2 kg ball is dropped from the roof of a building 230 m high. While the ball is falling to Earth, a horizontal wind exerts a constant force of 12.0 N on it.

(a) How far from the building does the ball hit the ground?

m

(b) How long does it take to hit the ground?

s

(c) What is its speed when it hits the ground?

m/s

4. A loaf of bread weighs 4.1 N on Earth.

(a) What should it weigh, in newtons, on the moon, where the acceleration due to gravity is one-sixth that on Earth?

N

(b) What should it weigh on Jupiter, where g is 2.64 times Earth's gravity?

N

5. [SFHS99 4.P.47.] A 4.66 kg briefcase is sitting at rest on a level floor.

(a) What is its acceleration?

m/s2

(b) What is its weight in newtons?

N

6. [SFHS99 4.P.52.] A 92 kg clock initially at rest on a horizontal floor requires a 656 N horizontal force to set it in motion. After the clock is in motion, a horizontal force of 556 N keeps it moving with a constant speed.

7. [SFHS99 4.P.56.] A car is traveling at 50.1 km/h on a flat highway.

(a) If the coefficient of friction between the road and the tires on a rainy day is 0.100, what is the minimum distance needed for the car to stop?

m

(b) What is the stopping distance when the surface is dry and the coefficient of friction is 0.600?

m

8. [SFHS99 4.P.64.] A hockey puck is hit on a frozen lake and starts moving with a speed of 13 m/s. Exactly 5.00 s later, its speed is 5.9 m/s.

(a) What is its average acceleration?

m/s2

(b) What is the average value of the coefficient of kinetic friction between puck and ice?

(c) How far does the puck travel during this 5.00 s interval?

m

9. [SFHS99 4.P.59.] A girl coasts down a hill on a sled, reaching the bottom with a speed of 8.6 m/s. The coefficient of friction between the sled's runners and the snow is 0.050, and the girl and sled together weigh 675 N. How far does the sled travel on the surface before coming to rest?

m

thanks