4 (a) Which one of these is a vector quantity? Put a cross (X) in the box next to your answer - Edexcel - GCSE Physics - Question 4 - 2018 - Paper 1

To find the velocity, we can use the formula for momentum, which is given by:

$p = mv$

where:

• $p$ is the momentum (90 kg m/s)
• $m$ is the mass (60 kg)
• $v$ is the velocity

Rearranging the formula to solve for velocity:

$v = \frac{p}{m}$

Substituting in the values:

$v = \frac{90 \text{ kg m/s}}{60 \text{ kg}} = 1.5 \text{ m/s}$

Thus, the velocity of the child and the cart is 1.5 m/s.