a block rests on a horizontal surface the normal force is 20N and the coefficient of static friction between the Block and the surface is 0.40 and the coefficient dynamic friction is 0.20 what is the magnitude of the frictional force exerted on the Block what block is at the rest​

Aboxcar traveling at 12 m/s approaches a string of 5 identical boxcars sitting stationary on the track. the moving boxcar collides and links with the stationary cars and they all move off together along the track. what is the final speed of the cars immediately after the collision? (you may take the mass of each boxcar to be 18,537 kg.)

When an object is heated it contracts. a. true b. false

In what direction does an applied force move an object