Question

Assume that a scale is in an elevator on Earth.

Answer 1

★ Remember :

The reading of scale of a man in an elevator :

• When the elevator moves upward with acceleration a, R = m(g + a)
• When the elevator moves downwards with acceleration a , R = m(g - a)
• When the elevator falls freely, we take a = g so, R = m(g - g) = 0
• When the lift is at rest or moves with uniform velocity, a = 0, so R = m(g - 0) = mg

A). The elevator moves up at a constant speed$.$

∴ Acceleration of elevator = 0

➠ R = mg

➠ 53 × 10

➠ R = 530N

B). It slows at 2m/s² while moving upward.

∴ Acceleration of elevator = -2m/s²

[Negative sign shows that speed decreases with time]

➠ R = m(g + a)

➠ R = 53(10 + (-2))

➠ R = 53 × 8

➠ R = 424N

C). It speeds up at 2m/s² while moving downward.

∴ Acceleration of elevator = 2m/s²

➠ R = m(g - a)

➠ R = 53(10 - 2)

➠ R = 53 × 8

➠ R = 424N

D). It moves downward at constant speed.

∴ Acceleration of elevator = 0

➠ R = mg

➠ R = 53 × 10

➠ R = 530N

Hope It Helps!