A crate of mass 100 kg is being pushed in a straight line across a horizontal floor at a constant speed of 4.0 m/s.
The coefficient of kinetic friction between the crate and
the floor is 0.3. Find the net force on the crate.

A. 0 N
B. 300 N
C. 400 N
D. 1200 N

Astone is dropped from the upper observation deck of a tower, 250 m above the ground. (assume g = 9.8 m/s2.) (a) find the distance (in meters) of the stone above ground level at time t. h(t) = (b) how long does it take the stone to reach the ground? (round your answer to two decimal places.) s (c) with what velocity does it strike the ground? (round your answer to one decimal place.) m/s (d) if the stone is thrown downward with a speed of 2 m/s, how long does it take to reach the ground? (round your answer to two decimal places.) s