Question

A block of mass 2.0 kg is pulled up on a smooth incline of angle 30° with the horizontal. If the block moves with an acceleration of 1.0 m/s², the power delivered by the pulling force at a time 4.0 s after the motion starts is ______ J/s.

विकल्प

• 45.00

• 47.00

• 46.00

• 48.00

Answer 1

A block of mass 2.0 kg is pulled up on a smooth incline of angle 30° with the horizontal. If the block moves with an acceleration of 1.0 m/s², the power delivered by the pulling force at a time 4.0 s after the motion starts is 48.00 J/s.

Explanation:

at t = 4 sec

if u = 0

then v = u + at

v = 0 + 1 × 4

v = 4 m/s

m = 2 kg

a = 1 m/s²

So, the power delivered at t = 4 sec

F – mg sin30° = 2 × 1

F = `(2 × 10)/2 + 2`

F = 12 N

P = `vecF . vecv`

= `mveca_r . vecv`

= 2 × 6 × 4

= 48 J/s