Question

3. Calculate the height through which a crane can lift a load of 4 t, when its motor of 4 HP operates for 10 s.
[Take, g = 10 ms]

​

Answer 1

h = 2 t = 10s mass = m = At = 4 x 1000 = 4000kg force F = mg = 4000 x 10N work done = F x h = 4000 x 10h Power = 4HP= 4x750w

p= w/t

4x750= 4000x10xh/10

h = 3000/4000= 0.75 m