Answer:
A:- 50 J
B:- 500 J
Explanation:
a) Given that a 25 N force is applied to move the box. Also the floor is having friction surface.
So in order to move the box, the floor should have friction of atleast 25 N.
∴ friction = 25 N
Work done = force * displacement of box
Given, the box is moved 2 m across the floor
So, Work done = friction * 2 m
= 25 * 2
= 50 J
b) Given, the box is having weight of 250 N weight
Gravitational force is acting on the box which is equal to (mass * gravity)
∴ Force = 250 N
The box is lifted 2 m above the floor.
So, displacement = 2 m
Work done = force * displacement of box
Work done = 250 * 2
= 500 J
Answer:
The speed of elevator fast and slows down shows through the diagram.
Explanation:
Given that,
Amanda has just entered an elevator. The elevator rises and stops at the third floor.
Let us consider the elevator at rest then the speed will be zero.
When elevator start from rest then the speed increases with constant acceleration and near the third floor it slow down with constant deceleration and finally becomes at rest at third floor.
We need to draw the diagram distance and time
Using given data,
First, the displacement A to B will be increases fastly and B to C the displacement increases slowly slowly.
Hence, The speed of elevator fast and slows down shows through the diagram.
<h2>
Option 3, 216 m is the correct answer.</h2>
Explanation:
We have initial velocity, u = 15 m/s
Time, t = 12 seconds
Final velocity, v = 21 m/s
We have equation of motion v = u + at
Substituting
21 = 15 + a x 12
a = 0.5 m/s²
Now we have equation of motion v² = u² + 2as
21² = 15² + 2 x 0.5 x s
s = 216 m
Displacement = 216 m
Option 3, 216 m is the correct answer.
They are both the same because of newton’s third law
When heat is applied, energy is applied. so since the state is a solid, there is no terms of energy being applied. Energy is basically "frozen" water turns to ice due to the object reaching its freezing point.