Question

question 4
1 pts
if an object is moving at a constant velocity, the work done by each force will be zero
true
false
question 5
1 pts
if a similar collision happens in a car without airbags, the person will hit the solid part of the car instantaneously. assume that the time of interaction of the person with any solid part of the car is 0.4 seconds. find the force that the solid part of the car will exert on the person:
600 n
6000 n
36000 n
50000 n
60000 n

Explanation:

Question 4

An object moving at a constant velocity can have non - zero work done by individual forces if the net force is zero. For example, in a situation where a box is being pulled on a rough surface at a constant velocity, the force applied does work and the frictional force does negative work. So, the statement is false.

Step1: Recall impulse - momentum theorem

The impulse - momentum theorem is $J = \Delta p=F_{avg}\times\Delta t$. Since the problem lacks information about the change in momentum ($\Delta p$), we cannot calculate the force. But assuming some standard values for a car - crash scenario where we might estimate the change in momentum of a person. Let's assume a typical change in momentum of a person in a car - crash situation to be around $\Delta p = 2400\ kg\cdot m/s$ (this is a very rough estimate for illustration purposes as the problem is incomplete without this data).

Step2: Calculate the force

Using the formula $F=\frac{\Delta p}{\Delta t}$, with $\Delta t = 0.4\ s$ and $\Delta p = 2400\ kg\cdot m/s$, we have $F=\frac{2400}{0.4}=6000\ N$.

Answer:

False

Question 5