Question

A 2.50 kg mass is pushed 10.0 m up a 30° incline. The work done is 125 J. What force is applied parallel to the incline to move the object?

a. 10.8 N

b. 12.5 N

c. 14.4 N

d. 24.5 N

Answer 1

Answer : --

• let this force = F
• Now the Object is acting by following force
• $mgcos\theta$ downward
• $mgsin\theta$ parallel to the incline but opposite to F
• so the total parallel force = $F- mgsin\theta$
• the work ddone by this force is given by
• $W = (F- mgsin\theta )d$
• $125= (F-2.5 \times 9.8 \times sin(30) )10$
• $12.5=F - 2.5 \times 9.8 \times sin(30)$
• $F= 12.5+2.5 \times 9.8 \times \frac{1}{2}$
• N
• so the option no. (4) is correct.