Question

physical science worksheet power
name______
show all work needed to solve problems 3 - 7!!!

1. what is the formula for calculating power?
2. what is the standard unit for power?
3. how much power (in w) must a student generate to do 475 j of work in 8.35 s?
4. a brick layer performed 12500 j of work in 105.2 s lifting bricks onto a scaffold for his partners laying the bricks. how much power (in w) did he have to generate to accomplish this?
5. if anna kate generated 750 w of power running sprints for 24.1 s, how much work did she do?
6. how much time would it take corey to generate 1075 w when he did 5639 j of work?
7. how much power (in w) must a 350 n person generate to move a 100 n object 23.7 m in 7.89 s? hint: substitute the work formula into the power formula!

Explanation:

Step1: Recall power formula

The formula for power is $P=\frac{W}{t}$, where $P$ is power, $W$ is work - done, and $t$ is time.

Step2: State unit of power

The standard unit for power is the watt (W), where $1\ W = 1\ J/s$.

Step3: Calculate power for student

Given $W = 475\ J$ and $t=8.35\ s$. Using $P=\frac{W}{t}$, we have $P=\frac{475\ J}{8.35\ s}\approx56.9\ W$.

Step4: Calculate power for brick - layer

Given $W = 12500\ J$ and $t = 105.2\ s$. Using $P=\frac{W}{t}$, we get $P=\frac{12500\ J}{105.2\ s}\approx118.8\ W$.

Step5: Calculate work for Anna Kate

Given $P = 750\ W$ and $t = 24.1\ s$. Rearranging the power formula $P=\frac{W}{t}$ to $W=P\times t$, we have $W=750\ W\times24.1\ s = 18075\ J$.

Step6: Calculate time for Corey

Given $P = 1075\ W$ and $W = 5639\ J$. Rearranging $P=\frac{W}{t}$ to $t=\frac{W}{P}$, we get $t=\frac{5639\ J}{1075\ W}\approx5.25\ s$.

Step7: Calculate power for person moving object

First, calculate work using $W = F\times d$. The force $F$ required to move the object is $F = 100\ N$ and $d = 23.7\ m$, so $W=100\ N\times23.7\ m = 2370\ J$. Given $t = 7.89\ s$, using $P=\frac{W}{t}$, we have $P=\frac{2370\ J}{7.89\ s}\approx300.4\ W$.

Answer:

1. $P=\frac{W}{t}$
2. Watt (W)
3. Approximately $56.9\ W$
4. Approximately $118.8\ W$
5. $18075\ J$
6. Approximately $5.25\ s$
7. Approximately $300.4\ W$