A 2-kg book falls off a shelf. It hits a student traveling 2 m/s. How much kinetic energy does the book have?

I have got a project about hacks so i need help

zhannawk [14.2K]

Hacks in real life are tricks to help solve a problem with a simple solution.

Say for example, add a pinch of salt to whip egg white faster.

5 0

2 years ago

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A pendulum is made by letting a 4 kg mass swing at the end of a string that has a length of 1.5 meter. The maximum angle that th

olga nikolaevna [1]

Answer:

Approximately $7.8\; \rm J$ .

Explanation:

The change in the gravitational potential energy of the pendulum is directly related to the change in its height.

Refer to the sketch attached. The pendulum is initially at $\rm P_2$ . Its highest point is at $P_1$ . The length of segment $\rm BP_2$ gives the change in its height.

The lengths of $\rm AP_1$ and $\rm AP_2$ are simply the length of the string, $1.5\; \rm m$ . To find the length of $\rm BP_2$ , start by calculating the length of $\rm AB$ .

$\rm AB$ forms a leg in the right triangle $\rm \triangle AP_1B$ . Besides, it is adjacent to the $30^\circ$ angle $\rm P_1\hat{A}B$ . Its length would be:

$\rm AB = 1.5 \times \cos(30^\circ) \approx 1.30\; \rm m$ .

The length of $\rm BP_2$ would thus be

$\rm BP_2 = AP_2 - AB = 1.5 - 1.30 \approx 0.20\; \rm m$ .

The change in gravitational potential energy can be found with the equation

$\Delta \mathrm{GPE} = m \cdot g \cdot \Delta h$ . In this equation,

$m$ is the mass of the object,
$g \approx 9.81\; \rm N \cdot kg^{-1}$ near the surface of the earth, and
$\Delta h$ is the change in the object's height.

In this case, $m = 4\; \rm kg$ and $\Delta h \approx 0.20\; \rm m$ . Therefore:

$\Delta \mathrm{GPE} = 4 \times 9.81 \times 0.20 \approx 7.8\; \rm J$ .

6 0

3 years ago

8

aev [14]

OD because Boyle’s law specifically states

4 0

3 years ago

1 - It is okay to use slang on a record as long as the auditor can interpret it.

vesna_86 [32]

1. false 2. false 3. true 4. not sure 5. b 6. b or d 7. not sure 8.not sure 9. not sure 10. c

lol sorry if i’m wrong on any i’m just using common sense

6 0

3 years ago

You should check your battery ___________.

podryga [215]

One should check the battery every week.

A battery if not maintained properly can cause it to die earlier or get damaged. The reasons why should the battery be checked regularly is that due to improper management of the battery and also the weather conditions, the battery usually gets corroded easily and the battery won't be able to work properly.

The connections must be checked properly so that the battery gets charged properly and should not die while driving.

5 0

3 years ago

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