Conservation of Momentum

We are given mass $m=25$ kg and velocity $v=2$ m/s. We need to find the momentum $p$.

The formula for momentum is $p=m\times v$ Substituting the values: $p=25\times 2=50\text{ kg m/s}$

The momentum of the shopping trolley is 50 kg m/s in the direction it is rolling. Always include units (kg m/s) in your answer.

We need momentum using $p=m\times v$, where $m=25$ kg and $v=2$ m/s. The correct operation is multiplication.

12.5 kg m/s comes from dividing $25÷2=12.5$. This confuses the momentum formula with rearranging for velocity. Eliminate this option.

27 kg m/s comes from adding $25+2=27$. Addition is never used in the momentum formula. Eliminate this option.

0.08 kg m/s comes from dividing $2÷25=0.08$. This is the wrong rearrangement. Eliminate this option.

The only remaining option is 50 kg m/s, which correctly uses $p=25\times 2=50$ kg m/s.

We are given momentum $p=3.6$ kg m/s and mass $m=0.06$ kg. We need to find velocity $v$.

Starting from $p=m\times v$, rearrange to: $v=\frac{p}{m}$

$v=\frac{3.6}{0.06}=60\text{ m/s}$

The tennis ball is travelling at 60 m/s. Dividing by a small decimal gives a large result, which makes sense for a fast-moving ball.

To find velocity from momentum and mass, rearrange $p=m\times v$ to get $v=p÷m=3.6÷0.06$.

0.216 m/s results from multiplying $3.6\times 0.06=0.216$. This uses the wrong operation — multiplication instead of division. Eliminate this option.

3.54 m/s results from subtracting $3.6-0.06=3.54$. Subtraction is not part of the momentum formula. Eliminate this option.

3.66 m/s results from adding $3.6+0.06=3.66$. Addition is also not used here. Eliminate this option.

The remaining answer is 60 m/s, correctly found from $v=3.6÷0.06=60$ m/s.