F=MA
F=(8 kg)(9.8 m/s)
F= 78.4 N
W=FD
W=(78.4 N)(7 m)
W=548.8 J
How this helps
Answer: There is not work done at the door because the door did not move.
Explanation: Work is defined as the movement done by a force.
So if you move to apply a force F in an object and you move it a distance D, the work applied on the object is
W = F*D
In this case, the secret agent pushes against the door, so there is a force, but the agent does not move the door, so D = 0, so there is no motion of the door, which implies that there is no work done at the door.
A. The amount of work increases.
Imagine you are pushing a box on a flat surface. Now imagine pushing it up a steep hill. It gets harder and that's how I remember this.
Hope this helps.
15 because i did the math, had this assignment, and also watch a video
Friction causes resistance against a moving object. It can cause an object to slow down, or stop when there’s enough friction…. I hope this helps