Numerical - Normal reaction on an elevator at constant velocity

Q.  If an elevator travels at constant velocity, the normal reaction R is given as ______
- Published on 21 Sep 15

a. m (g +a)
b. m (g - a)
c. mg
d. ma

ANSWER: mg
 

    Discussion

  • Sravanthi   -Posted on 15 Dec 15
    According to Newton's 2nd law, rate of change of linear momentum is directly proportional to impressed force.

    Force = mg + ma

    1) When lift moves at constant velocity, acceleration is zero.

    Therefore, force = mg + 0 = mg

    2) When lift undergoes downward acceleration, normal reaction is given as FR = m (g - a)

    3) When lift undergoes upward acceleration, normal reaction is given as FR = m (g + a)

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