Question

a girl is carrying a school bag of 3 kg mass on her back and moves 200m on a level road If g be 10 m/s square ,the work done by the girl against the gravitational force will be

Answer 1

Answer:

the amount of work done is expressed in equation: workdone= force ×distance. in this case, the total work done is zero as the displacement is perpendicular to the applied force.

Answer 2

Answer:-

$\pink{\bigstar}$ Work done $\large\leadsto\boxed{\rm\purple{0 \: J}}$

• Given:-

Mass of bag = 3 kg

Distance travelled = 200 m

acceleration = 10 m/s²

• To Find:-

Work done against the gravitational force

• Solution:-

We know,

$\large\boxed{\blue{\bf W = F . s \: cos \theta}}$

here,

W = work done

F = force

s = displacement

θ = angle made by force and displacement

Here, F is unknown so:-

$\large\boxed{\blue{\bf F = ma}}$

➙ $\sf F = 3 \times 10$

★ $\bf F = 30 N$

Now,

W = F.s cosθ

Direction of motion is perpendicular to direction of gravtional force so θ is 90°

➙ $\sf W = 30 \times 200 \times 90^{\circ}$

➙ $\sf W = 6000 \times 0 \dashrightarrow\bf\red{[\because cos90^{\circ} = 0]}$

★ $\bf W = 0 \: J$

Therefore, the work done by the girl against the gravity is 0 J.