Question

A block of mass 250 g slides down an incline of inclination 37° with a uniform speed. Find the work done against the friction as the block slides through 1.0 m. ?
Concept of Physics - 1 , HC VERMA , Chapter " Work and Energy"

Answer 1

Hello Dear.

Given :- A block of mass = 250 g = 0.25 kg.

Displacement (S) = 1.0 m & The angle θ = 37°

Refer to the attachment. In the diagram :- 

Now we know weight = mg
= 0.25 × 10  {as g = 10 m/s² }
= 2.5 N.

Displacement given here  = 1.0 m.

∴ work done = Force × displacement 
 as here Force = mg sin 37°
 Now, work done 
= mg sin 37° × 1.0
= 2.5 × 0.60
= 1.50 J.

Hence , work done against the friction is 1.5 J.



Hope it Helps.

Answer 2

Answer:

We know that acceleration towards an incline is always denoted as mg.sinФ where Ф is the angle of inclination.

Prerequisites

• Work Done = Force × Displacement

Force = Mass × Acceleration

⇒ Force = 0.25 kg × g sin Ф

⇒ Force = 0.25 × 10 × Sin 37 = 0.25 × 10 × 3/5 = 0.25 × 6 = 1.5 N

Displacement = 1 m

Hence Work Done = 1.5 N × 1 m = 1.5 J

Hope it helped !!

Thanks !!