Answer:
W = 1250 J = 1.25 KJ
Explanation:
The work done by the boy is due to the change in the position of the cement vertically. Hence, the work done in this case will be equal to the potential energy of the cement:
where,
W = Work done = ?
mg = W = weight of cement = 500 N
h = height covered = 2.5 m
Therefore,
<u>W = 1250 J = 1.25 KJ</u>
Answer:
At (approximately
.)
Explanation:
Note that the acceleration of the car between and
(
) is constant. Initial velocity of the car was
, whereas
at
. Hence, at
, this car would have travelled a distance of:
.
At , the truck would have travelled a distance of
.
In other words, at , the truck was
ahead of the car. The velocity of the car is greater than that of the truck by
. It would take another
before the car catches up with the truck.
Hence, the car would catch up with the truck at .