Question

While skateboarding at 19 km/h, Alana throws a tennis ball at 11 km/h to her friend Oliver. If Alana is the reference frame, the speed of the tennis ball is

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km/h.

Answer 1

Haven't taken physics but I would assume if her friend is standing in front of her that you would add up the speeds and get 30 km/hr.

Answer 2

Answer : Speed of tennis ball is 30 km/h.

Explanation :

Alana's speed on the skateboard is 19 km/h

She throws a tennis ball at 11 km/h

Alana is throwing a ball towards her friend Oliver.

That means the velocity of Alana and ball gets added up.

So, Speed of tennis ball is
`v_t=19\ km/h+11\ km/h=30\ km/h`