Problem 1

A 2.5 lbf block 'B' is moving with a velocity Vo of magnitude Vo = 6ft/s as it hits the 1.5 lbf sphere 'A', which is at rest and hanging from a cord attached at O. Knowing that the kinetic coefficient of friction is 0.6 between the block and the horizontal surface and the coefficient of restitution between the block and the sphere is 0.8, evaluate (a) the maximum height h reached by the sphere, and (b) the distance x traveled by the block.

Problem 2

A 0.12-oz bullet hits a suspended 15-lbf block of wood and becomes embedded in it.  The angle through which the wires supporting the block rotate as a result of the impact is measured and determined to be 7 degrees.  What is the bullet's velocity?

Problem 3

Two identical cars A and B are at rest on a loading dock with brakes released.  Car C, of a slightly different style but the same weight, has been pushed by dockworkers and hits car B with a velocity of 4.5 ft/s.  Knowing that the coefficient of restitution is 0.8 between B and C, and 0.5 between A and B, Determine the velocity of each car after all collisions have taken place.

Problem 4

Please help with details why answer is yes or No/True or false

1) If a particle moves along a curve with a constant speed, then its tangential component of acceleration is zero

2) The normal component of acceleration represents the time rate of change in the direction of the velocity

3) Work of the force exerted by a spring is positive when the spring is returning to its un-deformed position.

4) Friction is always negative

Forces which DO NOT do work

- A reaction at frictionless pin supporting rotating body

- Reaction at frictionless surface when a body is in contact moves along surface

- Weight of a body when it is centered.

5) The conservation of energy equation T1 +V1 = T2 +V2 can be applied if all of the forces that do work on the object are conservative.

6) A force that acts over a large interval of time but exerts a significant linear impulse is called an impulse force. FALSE, because these forces act for a very short time. Called impulsive forces. The product of the impulsive force and the time it acts is called the impulse. The impulse is equal to the change of momentum caused by the impulsive force.

7) The principle of impulse momentum is a vector equation that determines both the change of magnitude and direction of the velocity.

8) A coefficient of restitution of 1 means PERFECTLY ELASTIC.

9) A coefficient of restitution of 0 means PERFECTLY PLASTIC.