Question

Your roommate drops your wallet down to you from the third-floor window of your apartment, which is 11.5 m from the ground. What is the velocity of the wallet when you catch it? (assume you catch the wallet right before it hits the ground)

Answer 1

Answer:

15 m/s

Explanation:

Using the law of conservation of energy, potential energy equals kinetic energy hence

$mgh=0.5mv^{2}$

Therefore

$v=\sqrt{2gh}$

where g is the acceleration due to gravity, m is the mass of the object, h is the height and v is the speed of the wallet

Taking g as 9.81 then

$v=\sqrt{2\times 9.8\times 11.5}=15.02098532  m/s\approx 15 m/s$