Question

If a 1.0 kg ball travelling at 4.0 m/s strike a wall and bounces straight back at 2.0 m/s, what will be the impulse?

Answer 1

Answer:

2

kg m

s

of momentum is lost.

Explanation:

We have to find

Δ

p

, where

p

is the linear momentum.

The formula for momentum is

p

=

m

v

, where

m

is the mass of the body and

v

its velocity.

We have

p

1

and

p

2

.

Δ

p

=

p

2

−

p

1

.

The mass,

m

, does not change and is always

1

kg

.

For

p

1

:

v

=

4

m

s

So

p

1

=

1

⋅

4

=

4

kg m

s

For

p

2

:

v

=

2

m

s

So

p

2

=

1

⋅

2

=

2

kg m

s

Δ

p

=

p

2

−

p

1

`

Δ

p

=

2

−

4

Δ

p

=

−

2

kg m

s

Therefore

2

kg m

s

of momentum is lost.