Question

A pinball bangs against a bumper giving the ball a speed of 42cm/s if the ball has a mass of 50.0g what is the ball’s kinetic energy in joules

Answer 1

Explanation:

Given:-

mass=50g

velocity=42cm/s

To find:-

Kinetic energy

Solution:-

As we know that

${\boxed{\sf kinetic\:energy={\dfrac {1}{2}}mv^2}}$

• Substitute the values

${:}\longrightarrow$$\sf k.v={\dfrac {1}{{\cancel{2}}}}\times 50\times {\cancel{42}}^2$

${:}\longrightarrow$$\sf k.v=50\times 21^2$

${:}\longrightarrow$$\sf k.v=50×441$

${:}\longrightarrow$$\sf k.v=22050MJ$

• 1Joule=1000milijoules
• 22050MJ=${\dfrac {22050}{1000}}=22.05J$
• =22J(Approximately)

$\therefore$${\underline{\boxed{\bf Kinetic\:energy=22Joule}}}$