Phy need help 20 point

1. If 2.0 J of work is done in raising a 180 g apple, how far is it lifted?

2. A 2000 kg car accelereates from rest under the actions of two forces. One is a forward foce of 1140 N provided by traction between the wheels and the road. The other is a 950 N resistive force due to various frictional forces. Use the work-kinetic energy theorem( Net work=change in kinetic energy) to determine how far the car must travel for its speed to reach 2.0m/s .

3. A 2100 kg car starts from rest at the top of a driveway that is sloped at an angle of 20.0 degree with the horizontal. An average friction force of 4000N impedes the car's motion so that the car's speed at the bottom of the driveway is 3.8 m/s. What is the length of the driveway?

4. A 75kg bobsled is pushed along a horizontal surface by two athletes. After the bobsled is pushed a distance of 4.5 m starting from rest, its speed is 6.0 m/s. Find the magnitude of the net force on the bobsled.

5. A 40kg child is in a swing that is attached to ropes 2 m long. Find the gracitational potential energy associated with the child relative to the child's lowest postion inder the following conditions:
a. when the ropes make a 30 degre angle with the vertical
b. at the bottom of the circular arc

6. A bird is flying with a sped of 18m/s over water when it drops a 2kg fish. If the altitude of the bird is 5.4m and friction is disregarded, what is the speed of the fish when it hits the water?

7. A 755N diver drops from a board 10 m above the water's surface. Find the diver's speed 5 m above the water's surface. Then find the diver's speed just before striking the water.

8. If the diver in item 2 leaves the board with an initial upward speed of 2m/s, find the diver's speed when striking the water.

9. An runner leaps over a hurdle. If the runner's initial vertical speed is 2.2m/s, how much will the runner's center of mass be raised during the jump?