The book is lifted upward, but gravity points down, so the work done by gravity must be negative (so you can eliminate options 1 and 3).
The force exerted on the book by gravity has magnitude
<em>F</em> = <em>mg</em> = (10 N) (9.80 m/s^2) = 9.8 N ≈ 10 N
You raise the book 1.0 m in the opposite direction, so the work done is
<em>W</em> = (10 N) (-1.0 m) = -10 J
Answer:
<h2>1. Friction is A. a force</h2>
<h2>2. An unbalanced force is B. When the object moves and accelerates</h2>
All that business about the crane and the rope and the falling
is only there to confuse us.
The piano ended up 5 meters above the ground.
Potential energy = (mass) (gravity) (height)
= (200 kg) (9.81 m/s²) (5 m)
= (200 · 9.81 · 5) (kg-m²/s²)
= 9,810 joules .
Answer:
Explanation:
By energy conservation and work energy theorem we can say that after bullet hits the block, it will move on the rough floor and comes to rest
so here work done by frictional force = change in kinetic energy
so we know that
now by momentum conservation we have
