Question

Mechanical work done is equal to (symbols have their usual meanings)

• A. W $=$ s
• B. W $=$ FS cos$\alpha$ ($\alpha$ is angle between force and displacement vector)
• C. W $=$ F + S
• D. W$=$FS

Answer 1

Answer: (B)

W $=$ FS cos$\alpha$ ($\alpha$ is angle between force and displacement vector)

Mechanical work done is equal to the dot product between force vector and the displacement vector (in the direction of force).

Therefore we can write it as $W=FScos\alpha$