Question

What is the momentum of a 2 kg ball moving at 3 m/s

Answer 1

Answer:

Momentum is the product of mass and velocity, so

(

m

v

)

1

=

(

m

v

)

2

Only moving objects have momentum, so all the momentum beforehand is in the moving ball, so

(

m

v

)

1

=

2

k

g

×

3

m

s

−

1

=

6

N

s

This ball stops moving, and now only the

10

k

g

ball moves, so momentum after the reaction is

(

m

v

)

2

=

10

k

g

×

v

m

s

−

1

We know that this is equal to the momentum before, so

10

×

v

=

6

→

v

=

0.6

m

s

−

1

Now for the second part. Calculating kinetic energy is done by the equation

E

=

1

2

m

v

2

which, before the reaction, is

E

=

1

2

×

2

×

3

2

=

9

J

after the reaction, it will be

E

=

1

2

×

10

×

0.6

2

=

1.8

J

Overall, then, the kinetic energy lost is

Δ

E

=

9

−

1.8

=

7.2

J

or, as a percentage,

9

−

1.8

9

×

100

%

=

80

%

of the kinetic energy is lost.

Explanation:

follow

Answer 2

Answer:

6 kg times m/s^2

Explanation: