A speed boat requires 61 kW to move at a constant speed of 28 m/s. What is the resistive force in Newtons of the water at this speed

Your forehead can withstand a force of about 6.0 kN before fracturing, while your cheekbone can withstand only about 1.3 kN. Suppose a 140 g baseball traveling at 27 m/s strikes your head and stops in 1.1 ms What force does the baseball exert on your head? What is the magnitude of the force that stops the baseball?

If a 2.3 kg object is initially at rest on a frictionless, horizontal surface and subjected to a  10.2 N force in the positive x-direction over a distance of 4.1 meters, what will the object’s  final speed be? Assume the answer in in m/s.

If a 2 kg object is initially at rest on a frictionless, horizontal surface and subjected to a  13.7 N force in the positive x-direction over a distance of 3.25 meters, what will the object’s  final speed be? Assume the answer in in m/s.

A 20-Mg train is traveling at a speed of 50 m/s at an angle of 10o. But the driver noticed that the bridge 300-m ahead is missing. At once, he pulls the break, thus applying a frictional resistance of Ff = 1000 N. At the same time Super Botting pushes back the train with a force of Fs=(123)d +100, where d is the distance that the train travels before stopping. Determine the stopping distance d, and mention whether or not Superperson would be able to save the train.

A 149-g baseball is dropped from a tree 15.0 m above the ground. a) With what speed would it hit the ground if air resistance could be ignored? b) If it actually hits the ground with a speed of 8.00 m/s , what is the magnitude of the average force of air resistance exerted on it?

Istahp. A constant force F = 5.0 [N] is applied at a certain angle from the horizontal on a 0.50 [kg] block that is initially moving to the right at v₁ = 3.0 [m/s]. If the block stops after traveling a distance s = 0.80 [m], what is the angle in the figure? F Vi vf = 0 0. O 79° O 34° O 56° O 124°

A small diamond of mass 13.3 g drops from a swimmer's earring and falls through the water, reaching a terminal velocity of 2.1 m/s.   (a) Assuming the frictional force on the diamond obeys f = −bv, what is b (in kg/s)? (Round your answer to at least four decimal places.)  kg/s   (b) How far (in m) does the diamond fall before it reaches 90 percent of its terminal speed?  m

What is the magnitude of the force that stops the baseball? What force does the baseball exert on your head? Are you in danger of a fracture if the ball hits you in the forehead? On the cheek?

The man slides the 180-lb crate across the floor by pulling with a constant force of 30 lb. If the crate was initially at rest, how far will the crate move before its speed is 4.0 ft/s? The coefficient of kinetic friction between the crate and the floor is 0.15.