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3 years ago

Complete the sentence. Friction always ____________

Physics

2 answers:

luda_lava [24]3 years ago

7 0

Answer:

B- Opposes the motion

Explanation:

When two object touches each other. friction acts in a opposite direction to the motion of the object

kobusy [5.1K]3 years ago

7 0

B. Opposes the motion.

A marble rolling across a flat surface will not roll forever. This is due to friction. The marble rubs against the flat surface, slowing down until it finally stops.

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Compare and contrast the solar eclipse seen in this video to a lunar eclipse.

Crank

Answer: sadly, I can’t see the video. However, a lunar eclipse happens when the moon is hidden by the earth’s shadow. A solar eclipse occurs when the moon casts a shadow on the earth.

Explanation: I’m not completely sure if this is what you were looking for, but I hope it helps anyway.

8 0

3 years ago

A worker on the roof of a house drops his 0.58 kg hammer, which slides down the roof at constant speed of 6.69 m/s. The roof mak

shusha [124]

Answer:

17.3 m

Explanation:

Given that,

Mass of a hammer is 0.58 kg

Velocity with which the hammer slides is 6.69 m/s at constant speed.

The roof makes an angle of 18 ◦ with the horizontal, and its lowest point is 18.2 m from the ground. We need to find the horizontal distance traveled by the hammer between the time is leaves the roof of the house and the time it hits the ground. Firstly, we will find the time taken by the hammer when it reaches ground in vertical direction.

$y=y_0+v_ot +\dfrac{1}{2}gt^2$

Putting all the values,

$0=18.2+6.69t-\dfrac{1}{2}\times 9.8t^2\\\\-4.9t^2+6.69t+18.2=0\\\\t=\dfrac{-6.69+\sqrt{6.69^{2}-4\cdot-4.9\cdot18.2}}{2\cdot-4.9}, \dfrac{-6.69-\sqrt{6.69^{2}-4\cdot-4.9\cdot18.2}}{2\cdot-4.9}\\\\t=-1.36\ s\ \text{and}\ t=2.72\ s$

Neglecting negative value,

To find horizontal distance, multiply 2.72 s with the horizontal component of velocity.

$d=2.72\times 6.69\times \cos(18)\\\\d=17.3\ m$

3 0

3 years ago

Which of the following sentences does not contain a type of variation?

stepan [7]

Answer: A

Explanation:

7 0

3 years ago

Read 2 more answers

In electronic circuits:______.

trapecia [35]

Answer:

(a), (c) and (e) s correct.

Explanation:

a. the power used by a circuit is the resistance times the current squared.

The power is given by P = I^2 R, so the statement is correct.

b. electric and magnetic fields are transporting the energy.

false

c. electrons are transporting the energy.

The energy is transferred by flow of electrons. It is correct.

d. the power used by a circuit is the voltage times the current squared.

The power is given by P = V I, the statement is wrong.

e. the power used by a circuit is the current times the voltage.

The power is given by P = V I, the statement is correct.

4 0

3 years ago

During light activity, a 70-kg person may generate 200 kcal

Lerok [7]

Answer:

$2.75387\ ^{\circ}$

Explanation:

m = Mass of person = 70 kg

c = Specific heat of human body = $0.83\ J/kg^{\circ}C$

$\Delta T$ = Change in temperature

Time taken is 1 hour

Heat is given by

$Q=mc\Delta T\\\Rightarrow \Delta T=\dfrac{Q}{mc}\\\Rightarrow \Delta T=\dfrac{0.8\times 200\times 1}{70\times 0.83}\\\Rightarrow \Delta T=2.75387\ ^{\circ}C$

The rise in temperature is $2.75387\ ^{\circ}C$

3 0

4 years ago