pt 1.

A toy car with a mass of 2.35 kg is pushed with a force of 21.6 N. What is the acceleration of the car?

A) given the information: write the given information in the problem. If any Units need to be converted, make that conversion as a part of your given answer.

B) Equation: write the general equation you will need to solve this problem, then use algebra steps to isolate the variable you are solving if necessary.

C) substitute and calculate: substitute the given values into your equation and solve.

D) final answer: give your final answer with correct units rounded to the correct number of significant figures.

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pt 2.
1. A car is traveling down the interstate at 37.1 m/s. The driver sees a cop and quickly slows down. If the driver slows to 29.8 m/s in 3 seconds. What is the acceleration of the car?

2. While cleaning you lift an 87.3 N box up to a shelf that is 2.04 m above the ground. How much work was done on the box?

3. A child runs up the stairs and does 1250 j of work. If the child is generates 267 W of power, how long did it take for the child to run up the stairs?

4. A 8.642 kg rabbit is running across your back yard. If that rabbit has 125.6 j of Kinetic Energy, how fast is it running?

5. When using a simple machine you do 120 j of work on the machine. You notice that the machine gives you an output of 93 j. What is the efficiency of this machine?

6. A 212 kg bumper car is traveling 8.00 m/s when it rear ends a second 196 kg bumper car traveling 6.75 m/s. If the cars get stuck together, how fast are they traveling after the collision.

7. A wave is traveling through a string. If the wave has a wavelength of .23 m and a frequency of 12 hz, what is the speed of the wave?

8. Find the wavelength of blue light if it’s frequency is Hz. (Hint: remember the speed of light).

9. The speed of sound in air is about 343 m/s. If you scream and a friend hears you 0.287 s later, how far away is your friend?

Respuesta :

Explanation:

pt1.

From the question,

m=2.35kg

F=21.6N

a=?

Given that,

[tex]F =ma[/tex], where F= force, m=mass and a= acceleration,.

By substitution we obtain,

[tex]21.6 = 2.35 \times a[/tex]

Dividing through by 2.35

[tex] \implies \frac{21.6}{2.35} = \frac{2.35 \times a}{2.35} [/tex]

[tex] \implies a = 9.19 \: {ms}^{ - 2} [/tex]

pt2.

2.From the question,

F=87.3 N and S= 2.04 m

Given that,

W=F×S

where

W=work done,

F=force,

and S=displacement

This implies that;

W=87.3×2.04

W=178.092J

3.

From the question,

P=267 W

W=1250 J

t=?

Given that, [tex]P= \frac{W}{t} [/tex]

where,

P=Power

W=work done, and

t= time

By substitution, we obtain

[tex]267 =\frac{1250}{t}[/tex]

cross multiplying we obtaion

[tex]267 \times t=1250[/tex]

Dividing through by 267, we get

[tex] \implies \frac{267 \times t}{267} = \frac{1250}{267} [/tex]

[tex]t = \frac{1250}{267} = 4.68s [/tex]

4.

From the question,

the mass of the rabbit, m=8.642 kg

Kinetic Energy,K.E of the rabbit =125.6 J

[tex]K. E = \frac{1}{2}m {v}^{2} [/tex]

where, m=mass and v=speed

By substitution, we get

[tex]125.6 = \frac{1}{2} \times 8.642 \times {v}^{2} [/tex]

[tex] \implies 125.6 \times 2= 8.642 \times {v}^{2} [/tex]

[tex] \implies251.2= 8.642 \times {v}^{2} [/tex]

Dividing through by 8.642.

[tex] \implies \frac{251.2}{8.642} = \frac{8.642 \times {v}^{2} }{8.642} [/tex]

Take positive square root of both sides

[tex] \implies v= \sqrt{ \frac{251.2}{8.642}} [/tex]

[tex]\implies v= 5.32{ms}^{-1}[/tex]

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