An astronaut on the moon drops a rock from rest. The rock falls 0.8m in one second of falling time. If the dropped rock fell for a total of two seconds of time instead of 1 second, then the distance traveled would be:. A) The same.
B) Doubled.
C) Tripled.
D) Quadruple.
E) None of the above.

D) Quadruple.

Explanation:

We will use the second equation of motion to solve this problem:

where,

s = distance travelled by the rock

vi = initial speed of rock = 0 m/s

t = time taken

g = acceleration due to gravity on the surface of the moon

Therefore,

----------- equation (1)

Now, we double the time:

using equation (1):

s' = 4s

Hence, the correct option is:

D) Quadruple.

12000j is work done

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.