Q

# Help me answer: A rocket with a mass of 500 grams is launched straight up. It achieves a velocity of 20.0 m/s in 2.00 seconds. The average thrust force of the engines on the rocket is

A rocket with a mass of 500 grams is launched straight up. It achieves a velocity of 20.0 m/s in 2.00 seconds. The average thrust force of the engines on the rocket is

• Option 1)

7.50 N.

• Option 2)

9.90 N.

• Option 3)

12.0 N.

• Option 4)

13.5 N.

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As we learnt

Power if the force is constant -

$P=\frac{dw}{dt}= P= \vec{F}\cdot \vec{v}$

- wherein

$\vec{F}\rightarrow force$

$\vec{v}\rightarrow velocity$

$V=u+at$     $u=o$

$\Rightarrow v=at$

$\Rightarrow 20=2a$ $\Rightarrow a=10ms^{-2}$

$F= m (g+a)=0.5 (9.8+10)$

$F= 19.8 \times 0.5=9.9$

Option 1)

7.50 N.

This option is incorrect

Option 2)

9.90 N.

This option is correct

Option 3)

12.0 N.

This option is incorrect

Option 4)

13.5 N.

This option is incorrect

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