Question

A 500g ball moves in a horizontal circle 40cm in radius at 4m/s, its centripetal acceleration i
a) 10 m/sec2
b) 20 m/sec2
c) 40 m/s or 80 m/s​

Answer 1

centripetal acceleration =$\frac{v^2}{r} \\==>\frac{4^2}{40} \\a_c=16/40\\a_c=0.4 m s$

Answer 2

Concept:

• Uniform circular motion
• Centripetal acceleration
• Centripetal Forces

Given:

• Mass of the ball = 500 g = 0.5 kg
• Horizontal circle of radius R = 40 cm = 0.4 m
• Speed of ball v = 4 m/s

Find:

• The centripetal acceleration of the ball

Solution:

We know that the centripetal force of an object undergoing uniform circular motion is F = mv^2/R

We also know that F = ma

The centripetal acceleration a = F/m = Centripetal force/ mass of the object

a = mv^2/mR

a = v^2/R

a = (4 m/s)^2/0.4 m = (16 m^2/s^2)/0.4m = 40 m/s^2

The centripetal acceleration is 40 m/s^2. So the correct option is C.

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