Sunday, May 17, 2009

Calculating the Velocity of a Body in Oscillational Motion

Oscillation is a type of motion where a body move back and forth motion about a pivot point. Moving swing is an example for such motion.
Here is a word problem to determine the velocity of moving swing. Balanced or unbalanced forces when applied on any body there occur a motion and the speed at which the body moves is velocity of that body.

Topic : Velocity of Moving Body

Since Potential Energy is equal to Kinetic energy in the system, m*g*h = 1/2*m*v2 is the formula to find velocity of a body with mass m, height h and g is constant gravitational force.

Question : A 40 kg girl is swinging on a 3m long swing. At her maximum height, the swing makes an angle of 40 degrees with the vertical rest position. Determine the girl’s maximum speed, ignoring frictional effects.?

Solution :

Mass= 40 Kg

Height =3*sin (40)

Here PE = KE

Mgh=1/2mv2

V2 = 2*g*h = 2*9.8*3*sin (40) = 12.59

V= 3.55 m/sec
The girl’s maximum speed, V= 3.55 m/sec


Whenever you have to solve similar kind of question, like finding velocity or any unknown qantities, consider the same formula substitute the values and calculate.

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