Question

A 4.40 kg model rocket is launched, shooting 53.0 g of burned fuel from its exhaust at an average velocity of 650 m/s. What is the velocity of the rocket

Answer 1

Answer:

Given data:

Mass of the model rocket,

m

1

=

4.40

k

g

m1=4.40 kg

Mass of the fuel,

m

2

=

53.0

g

=

0.053

k

g

m2=53.0 g=0.053 kg

Average velocity of the exhaust gases,

v

2

=

650

m

/

s

v2=650 m/s

Let the velocity of the rocket be

v

1

.

v1.

From the conservation law of the linear momentum, the change in momentum must be equal to zero.

Thus,

m

1

v

1

+

m

2

v

2

=

0

m1v1+m2v2=0

Here, we have assumed that the velocity along the forward direction as positive.

Plugging in values,

4.40

×

v

1

+

0.053

×

(

−

650

)

=

0

4.40×v1+0.053×(−650)=0

On solving,

v

1

=

7.82

m

/

s

.

v1=7.82 m/s.