Question

A child shoots a ball with a slingshot off the roof of a skyscraper at an angle paralle with the ground. The ball has an initial velocity of 10 m/s. After the ball travels for 5 seconds how much fast will it be traveling? ((I don't know need help​

Answer 1

Answer:

Not accounting for friction, the ball would be falling at 14.0 m/s

Explanation:

Without a coefficient of kinetic friction being provided, we'll have to assume zero friction between the ball and the air.

In that case, the ball's horizontal speed will remain 10 m/s.  To find it's velocity in five seconds then, we just need to take gravity into account.

Let's assume acceleration from gravity is 9.8 m/s².  We can simply multiply that by five seconds to find out how fast it's going at that point:

$9.8\frac{m}{s^2} \times 5s\\= 49 \frac{m}{s}$

So at five seconds, the ball is moving horizontally at 10 m/s and vertically at 479 m/s.

Now we can simply take the hypotenuse between those two vectors to get the actual speed:

$s = \sqrt{9.8^2 + 10^2}\frac{m}{s}\\s = \sqrt{96.04 + 100}\frac{m}{s}\\s = \sqrt{196.04}\frac{m}{s}\\s = 14.0 \frac{m}{s}$

So lacking air to slow it down, the ball would be going at approximately 14.0 metres per second.