Calculate the normal force on a 20 kg object being pushed along the ground with 10N of force.

4. 50x10= 500m/s 5. 52m/s

The magnets are probably damaged or there not strong enough to attached to the refrigerator

Ithink the answer is d

Ke reqd to move from 0 to 50 will be proportional to 50x50 or 2500. this is equal to w.  to change vel from 50 to 150 you need energy prop to 22500 - 2500 = 20,000. this corresponds to 8w.  best answer is a) . work reqd is prop to velocity squared.