Question

A ruler is dropped, and the reaction time is measured by the distance it falls before being caught. If the distance is 44 cm, calculate the reaction time.

a) 0.2 seconds
b) 0.4 seconds
c) 0.6 seconds
d) 0.8 seconds

Answer 1

To calculate the reaction time, use the equation for free fall and solve for time. The reaction time is approximately 0.297 seconds. To find the distance traveled in a car when the reaction time is twice the time it took your foot to move from the gas pedal to the brake, use the equation for distance and solve for distance. The distance traveled is approximately 17.82 meters.

Step-by-step explanation:

To calculate the reaction time, we first need to determine the time it took for the ruler to fall. The distance traveled by the ruler when dropped is 44 cm. Using the equation for free fall d=1/2gt^2, where d is the distance, g is the acceleration due to gravity (9.8 m/s^2), and t is the time, we can solve for t by rearranging the equation to t=sqrt(2d/g). Plugging in the values, we get t=sqrt(2*0.44/9.8)=0.297 s.

Thus, the reaction time is approximately 0.297 seconds.

To answer the second part of the question, if the time it took your foot to go from the gas pedal to the brake was twice your reaction time (0.594 s), we can calculate the distance traveled using the equation d=vt, where d is the distance, v is the velocity (30 m/s), and t is the time. Plugging in the values, we get d=30*0.594=17.82 m.

Therefore, the distance traveled in a car moving at 30 m/s if the time it took your foot to go from the gas pedal to the brake was twice your reaction time is approximately 17.82 meters.