Answer to Question #289751 in Mechanics | Relativity for Hms

Question

What average force is required to push a 20.0 -kg stroller with your toddler in it for 5.0 seconds if the weight of the toddler is 15.0 kg? Suppose that you can push with a speed of 1 m/s and the stroller is initially at rest

Answer 1

Explanation & Calculation

• Since the system starts with zero and attains some speed, it has an acceleration.
• That needs to be calculated.
• Once it is calculated, you can calculate the acceration.
• Here, the stroller with the toddler, the combined system is considered for all the calculations

$\qquad\qquad \begin{aligned} \small v&=\small u+at\\ \small a&=\small \frac{v-u}{t}=\frac{1\,ms^{-1}-0}{5.0\,s}\\ &=\small 0.2\,ms^{-2} \end{aligned}$

• Now for the entire system, Newton's second law can be applied.

$\qquad\qquad \begin{aligned} \small F&=\small ma\\ \small F_{avg}&=\small (20.0\,kg+15.0\,kg)\times0.2\,ms^{-2}\\ &=\small 7.0\,N \end{aligned}$