Question

A baseball with a mass of 151 g is thrown horizontally with a speed of 39.5 m/s (88 mi/h) at a bat. The ball is in contact with the bat for 1.10 ms and then travels straight back at a speed of 45.1 m/s (101 mi/h). Determine the average force exerted on the ball by the bat.

Answer 1

Henry's study included 200 subjects in total, divided equally into two groups, one receiving a drug and the other a placebo. The double-blind design aimed to test the drug's efficacy without bias from expectations. The study concluded with no significant difference in the fear levels between the two groups.

Step-by-step explanation:

Henry's study involved 200 subjects in total. These subjects were divided into two groups: one group received the drug Fearnot, and the other group was given a placebo, which is a sugar pill with no therapeutic effect. This method is a typical approach in clinical trials to determine the efficacy of a new treatment while controlling for the placebo effect. The study design ensures that neither the participants nor the researchers know who is receiving the actual treatment or the placebo. This double-blind setup helps to prevent bias and ensures that any differences in outcomes can be attributed to the drug itself rather than expectations or beliefs about being treated. As Henry found no difference in the level of fear between the two groups, we can infer that the experimental drug did not show efficacy in reducing fear of public places for the subjects.

Answer 2

the average force exerted on the ball by the bat is 11,613.27 N

Step-by-step explanation:

Given;

mass of the baseball, m = 151 g = 0.151 kg

initial velocity of the baseball, u = 39.5 m/s

final velocity of the baseball, v = 45.1 m/s

time of action, t = 1.10 ms = 1.10 x 10⁻³ s

The average force exerted on the ball by the bat is calculate as;

`F = ma = (m(v-u))/(t) \\\\F = (0.151(45.1-(-39.5)))/(1.10* 10^(-3)) \\\\F = (0.151(45.1\ +\ 39.5))/(1.10* 10^(-3)) \\\\F = 11,613.27 \ N`

Therefore, the average force exerted on the ball by the bat is 11,613.27 N