Monday, October 4, 2010

Force

1. Three blocks are in contact with each other on a frictionless horizontal surface.The masses of the blocks are m1 = 1 kg , m2 = 2 kg, m3 = 3 kg. A horizontal force F = 24 N is applied on m1.

a. Find the net force on each block.
b. Find magnitude of the contact forces between the blocks.

2. Two blocks, joined by a string, have masses of 6.0 and 9.0 kg. They rest on a frictionless horizontal surface. A 2nd string, attached only to the 9-kg block, has horizontal force = 30 N applied to it. Both blocks accelerate. Find the tension in the string between the blocks.

3. A 1000-kg car moving north at 100km/h brakes to a stop in 50m. What are the magnitude and direction of the force?

4. A mass, m1, accelerates at 3 m/s/s when a force, F, is applied. A second mass, m2, accelerates at 1.0 m/s/s when F is applied to it.
a. Find the value of the ratio m1/m2.
b. Find the acceleration of the combined mass ( m1 + m2) under the action of the force, F.

5. A 5.0 kg missile is projected from rest to a speed of 4.5 x 103 m/s. How much time is required to do this by a net force of 5.3 x 105 N?