Aball is whirled on the end of a string in a horizontal circle of radius r at constant speed v. which way(s) can increase the centripetal acceleration of the ball by a factor of 9?
a) increasing both the radius and the speed by a factor of 9
b) keeping the speed fixed and decreasing the radius by a factor of 9
c) keeping the radius fixed and increasing the speed by a factor of 9
d) keeping the speed fixed and increasing the radius by a factor of 9
e) decreasing both the radius and the speed by a factor of 9
f) keeping the radius fixed and increasing the speed by a factor of 3

A, B and F are the right answers

Explanation:

The formula is

A) Increasing both the radius and the speed by a factor of 9

=

which means the acceleration will increase by a factor of 9

B) Keeping the speed fixed and decreasing the radius by a factor of 9

=

which means the acceleration will increase by a factor of 9

C) Keeping the radius fixed and increasing the speed by a factor of 9

=

It will increase the acceleration 81 times

D) Keeping the speed fixed and increasing the radius by a factor of 9

=

It will decrease the acceleration by 9 times

E) decreasing both the radius and the speed by a factor of 9

=

It will decrease the acceleration by 9 times

F) Keeping the radius fixed and increasing the speed by a factor of 3

=

It will increase the acceleration by 9 times

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.

conduct current i mean it makes sense