Question

A girl, moving at 8.8 m/s on in-line skates, is overtaking a boy moving at 4.3 m/s as they both skate on a straight path. The boy tosses a ball backward toward the girl, giving it speed 11.4 m/s relative to him. What is the speed of the ball relative to the girl, who catches it?

Answer 1

Answer:16.5 m/s

Step-by-step explanation:

Given

Velocity of boy
`(v_b)=4.3 m/s`

velocity of girl
`(v_g)=8.8 m/s`

velocity of ball relative to boy
`(v_(Bb))=11.4 m/s` backward

Now We have to find velocity of ball relative to girl

Representing it in vector form

`v_b=4.3\hat{i}`

`v_g=8.8\hat{i}`

`v_(Bb)=-11.4\hat{i}`

and

`v_(Bb)=v_B-v_b`

`v_B=v_(Bb)+v_b`

`v_B=-11.4\hat{i}+4.3\hat{i}=-7.1\hat{i}`

therefore velocity of ball relative to girl

`v_(Bg)=v_B-v_g=-7.1\hat{i}-8.8\hat{i}=-16.5\hat{i}`