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# Classical Mechanics

1. You are loading a spring loaded dart gun and do an amount of work W such that the spring is only 1/3 compressed. How much additional work must you do to fully compress it from 1/3 to fully compressed? Answer in terms of W.

2. A large man tosses a small child onto a large pile of leaves. During the toss, the man exerts _________ force (magnitude) on the child as compared to the force the child exerts on him while the acceleration (magnitude) of the man is _________ than the child's.

a. a larger & smaller.
b. the same & smaller.
c. the same & the same.
d. a larger & the same.

3. Two bodies are falling with negligible air resistance, side by side, above flat, horizontal ground. If one of the bodies is given an additional horizontal acceleration during its descent, it:

a. strikes the ground at the same time as the other body
b. has the vertical component of its acceleration altered
c. strikes the ground earlier than the other body
d. follows a straight line path along the resultant acceleration vector
e. has the vertical component of its velocity altered

#### Solution Preview

1. Work done in compressing the spring gets stored as the potential energy of the spring. PE stored in a spring of spring constant k, compressed to a length x from its normal position is given by ½ kx^2.

When compressed L/3, PE of the spring = ½ k(L/3)^2 = kL^2/18 = W

When fully ...