Aboy is pushing a 5.0 kg box across the floor, causing it to accelerate at 7.0 m/s2. if the boy is pushing with a force of 40.0 n on the box, what is the approximate magnitude of the frictional force?

Which of the following is not am example of a polymer? protein nylon kevlar concreta

A- a of 8.00 cm a of 34.0 nc. a , -, a of 25.0 nc is on of a of 15.0 cm .be toto aof ? a) b) c) j d) e)

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •