Question

A pendulum has a mass of 3 kg and is lifted to a height of 0.3 m. What is the maximum speed of the pendulum?

Answer 1

is the equation 1/2mv^2 ?
i thought so but i dont have a "v" so im not sure

Answer 2

Does this question comes with a diagram??

Answer 3

no @LastDayWork

Answer 4

Use energy balance -
PE of initial case = KE of final case

Answer 5

what do you mean? @LastDayWork

Answer 6

1/2mv^2 = mgh

Answer 7

I should have written it ^^ in reverse
Change in Potential energy = Change in Kinetic energy
mgh = 1/2mv^2

Actually, there is a - sign in the above equation. But personally i will suggest to find only magnitude from mathematics and try to deduce sign by using physics.

Answer 8

use the conservation of energy, as @LastDayWork suggests.

Answer 9

what should i use for v? @LastDayWork

Answer 10

@abbyisaprincess
Srry, i didn't check the notification.

The question asks you to find the max speed.
This is what you will get by energy balance.

Answer 11

@abbyisaprincess the v is the only thing you don't know, so rearrange the equation to solve for the v

Answer 12

1/2 x m x v^2 = m x g x h

cancel out the m

and solve for v.

therefore

v^2= (g x h) / 0.5
= square root of [(9.8 x 0.3) / 0.5]