A stone of 5g is projected with a rubber catapult. If it is stretched through a distabsce of 7cm by an average force of 70N Calculate the velocity of the stone when released

1 answer

To calculate the velocity of the stone when released, we can use the concept of work done by the catapult. The work done by the catapult is equal to the kinetic energy of the stone when released.

Given:
- Mass of the stone (m) = 5g = 0.005kg
- Stretched distance (d) = 7cm = 0.07m
- Force applied by the catapult (F) = 70N

First, we need to calculate the work done by the catapult:
Work done (W) = Force * Distance
W = 70N * 0.07m
W = 4.9 Joules

Next, we can calculate the kinetic energy of the stone when released:
Kinetic energy (KE) = 0.5 * mass * velocity^2
KE = 0.5 * 0.005kg * v^2
KE = 0.0025 * v^2

Since the work done by the catapult is equal to the kinetic energy of the stone when released, we can set the two equations equal to each other:
4.9 = 0.0025 * v^2
v^2 = 4.9 / 0.0025
v^2 = 1960
v = √1960
v ≈ 44.3 m/s

Therefore, the velocity of the stone when released by the rubber catapult is approximately 44.3 m/s.