Answer:
6370 J
Explanation:
By the law of energy conservation, the work done by the student would be the change in potential enegy from 1st floor to 3rd floor, or a change of 13 m

where m = 50kg is the mass of the student, g = 9.8 m/s2 is the gravitational constant and h = 13 m is the height difference

Metals in general, are good heat conductors
Answer:
It is due to the large impulse is imparted on the flour.
Explanation:
A ball is moving faster.
When a ball is moving faster strikes to the flour, the change in momentum is large and thus the impulse imparted on the flour is large.
Impulse = change in momentum
So, as the flour experiences large impulse and large momentum so that the flour spreads out.
If the change in momentum is large so the flour spreads out is more.
Answer: small cars can stop and go fast big trucks can not
Explanation:
Answer:68m/s
Explanation:
Frequency=17Hz
Wavelength=4metre
Wave speed=frequency x wavelength
Wave speed =17 x 4
Wave speed =68m/s