Which type of energy is stored while stretching the catapult? How this energy is obtained?
While stretching the catapult, potential energy is stored in it. This energy is obtained by doing work against the restoring force of the string.
If a machine lifts a load of 500N upto 40m in 2 minutes, how much is the power of the machine?
Solution:
Here,
Load lifted (F) = 500 N
Height (h) = 40 m
Time (t) = 2 minutes = 2 x 60 s = 120 s
Work done (W) = F x h = 500 x 40 = 20 000 J
To find: Power (P) = ?
We know,
Power (P) = W / t = (20000 / 120)
= 166.67 W
Hence, the required power of the machine is 166.67 Watt.