Question

In the lab, a student is investigating the effects of texting and driving. The student determines their reaction time by having a friend release a meter stick at random intervals while the driver sends text messages. The student, on average, catches the meter stick after it has fallen 0.64m. How far will the student travel in a car moving at 35 m/s horizontally before reacting?

A) 0.64m
B) 12.5m
C) 9.0m
D) More information is needed to calculate the distance.

Answer 1

To calculate the distance traveled in a car before reacting, we need to determine the reaction time. The distance traveled during this time is equal to the velocity of the car multiplied by the reaction time. In this case, the student will travel 35 times their reaction time in the car.

This correct answer is B)

Step-by-step explanation:

To determine the distance traveled by the student before reacting, we can use the equation for horizontal motion:

Distance=Speed×Time

We know the speed of the car (35m/s), but we need to find the reaction time. The distance the meter stick falls (0.64m) can be related to the time it takes for the student to react.

The equation for the distance fallen (d) under constant acceleration due to gravity (g) can be expressed as:

d= 1/2gt2

Where: d is the distance fallen (0.64m), g is the acceleration due to gravity (9.8 m/s2),

t is the time of reaction.

Let's solve for

t= √2d/g

Substitute the given values:

t= √2×0.64m/9.8m/s2

t≈0.362s

Now, we can use the reaction time to find the distance traveled by the car:

Distance=Speed×Time

Distance=35m/s×0.362s

Distance≈12.67m

So, the student will travel approximately 12.67m before reacting. The closest option is B) 12.5m.

This correct answer is B)