Answer:
1) Chemical to mechanical (calories -> muscle contractions)
2) mechanical to mechanical (muscle -> motion)
3) mechanical to thermal (motion -> heat from the body causes sweating)
The potential energy is stored in the body chemically (via food). That potential energy is then released when the body is put in motion.
Explanation:
Answer:

Explanation:
Given that
Mass of rifle = M
Initial velocity ,u= 0
Mass of bullet = m
velocity of bullet = v
Lets take final speed of the rifle is V
There is no any external force ,that is why linear momentum of the system will be conserve.
Initial linear momentum = Final linear momentum
M x 0 + m x 0 = M x V + m v
0 = M x V + m v

Negative sign indicates that ,the recoil velocity will be opposite to the direction of bullet velocity.
Answer:
Volume = 24 cm^3
Explanation:
We recall that the volume of the box is calculated via the formula:
Volume = length * height * width
and that in a product, the number of significant figures for the result should coincide with the number of significant figures of the factor that has the least of them.
In this case, all measures have the same number of significant figures: two. so we calculate the product, and then limit the answer value to exactly two significant figures:
Volume = 4.1 cm * 2.8 cm * 2.1 cm = 24.108 cm^3, which must be rounded to two significant figures as: 24 cm^3