Answer:
<em>The skydiver needs 0.71 seconds to reach 7 m/s</em>
Explanation:
<u>Free Fall Motion
</u>
When an object is dropped in free air (no friction) from a certain height h, it follows a free-fall motion, whose acceleration is due exclusively to gravity. The speed at a moment t when the object is dropped (from rest) is:

We need to find How long does the skydiver needs to reach 7 m/s. We solve for t



The skydiver needs 0.71 seconds to reach 7 m/s
The change in internal energy of the gas is

.
In fact, the 1st law of thermodynamics states that the change in internal energy of a system is equal to the amount of heat given to the system (Q) plus the work done on the system (W):

In this example, no work is done on the bottle so W=0, while the heat given to the system is

, so the change in internal energy of the gas is
Answer: mass = 48.47 kg.
Explanation:
Formula : Weight = mg , where m = mass of body , g= acceleration due to gravity .
Given: Weight = 475 N

Substitute all values in formula , we get

Hence, his mass = 48.47 kg.
A. 4% you divide 2000 to 500 and you get 4 which is your answer