Question

1. a net force of 15 n is exerted on an encyclopedia to cause it to accelerate at a rate of 5 m/s². determine the mass of the encyclopedia. a. 0.33 kg b. 2 kg c. 3 kg d. 45 kg 3. if the mass of an object doubles, then the acceleration is ______ when the force is kept the same. a. doubled b. halved c. kept the same

Explanation:

Step1: Identify the formula

Use Newton's second - law $F = ma$, where $F$ is force, $m$ is mass and $a$ is acceleration. We need to find $m$, so we can rewrite the formula as $m=\frac{F}{a}$.

Step2: Substitute the given values

Given $F = 15\ N$ and $a = 5\ m/s^{2}$. Substitute into $m=\frac{F}{a}$, we get $m=\frac{15}{5}$.

Step3: Calculate the mass

$m = 3\ kg$.

For question 3:

Step1: Recall Newton's second - law

$F=ma$. If $F$ is constant and the new mass $m_{new}=2m_{old}$, then $F = m_{new}a_{new}=2m_{old}a_{new}$. Also $F = m_{old}a_{old}$.

Step2: Equate the two expressions for $F$

Since $m_{old}a_{old}=2m_{old}a_{new}$, we can cancel out $m_{old}$ (assuming $m_{old}
eq0$) and get $a_{old}=2a_{new}$, or $a_{new}=\frac{a_{old}}{2}$. So the acceleration is halved.

Answer:

1. c. 3 kg
2. b. Halved