Answer:
D
Explanation:
they are both poor conductors of heat so that people who works with heat won't get affected by heat
Answer:
a) 
b) 
Explanation:
Given:
- mass of the ball thrown up,

- initial velocity of the ball thrown up,

- height above the ground from where the ball is thrown up,

a)
Maximum height attained by the ball above the roof level can be given by the equation of motion.
As,

where:
final velocity at the top height of the upward motion 
acceleration due to gravity
height of the ball above the roof
Now,


Therefore total height above the ground:



b)
Now we find the time taken in raching the height
:

final velocity at the top of the motion 
So,


Now the time taken in coming down to the ground from the top height:

where:
is the initial velocity of the ball in course of coming down to ground from the top 
Here the direction acceleration due to gravity is same as that of motion so we are taking them positively.


Therefore the total time taken in by the ball to hit the ground after it begins its motion:



The boulder has a weight of W=2400 N. The weight of an object is the product between its mass m and the gravitational acceleration g:

Rearranging the relationship, we can calculate the mass of the boulder:

We are told that Superman applies a horizontal force to this object, and as a result, the acceleration of the boulder is

. We can find the force applied by using Netwon's second law of motion: