C) Explain the following.<br>Keftles, cooking pans and iron boxes have polished surfaces

A 1000 kg car is rolling slowly across a level surface at 1m/s, heading toward a group of small innocent children.

Ne4ueva [31]

Answer:

The force is -1620.73 N.

Explanation:

Given that,

Mass of car = 1000 kg

Velocity = 1 m/s

Distance = 2 m

Angle = 30°

We need to calculate the force

Using formula of work done

$W_{net}=K_{f}-K_{i}$

$F\times d=K_{f}-K_{i}$

$Fd\cos\theta=-K_{i}$

$F=\dfrac{-K_{f}}{d\cos\theta}$

$F=-\dfrac{\dfrac{1}{2}mv^2}{d\cos\theta}$

Put the value into the formula

$F=-\dfrac{\dfrac{1}{2}\times1000\times(1)^2}{2\times\cos30}$

$F=-1620.73\ N$

Hence, The force is -1620.73 N.

7 0

3 years ago

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Two parallel plates that are initially uncharged are separated by 1.2 mm. What charge must be transferred from one plate to the

Gnoma [55]

Answer: 55.52 *10^-6 C= 55.52 μC

Explanation: In order to solve this question we have to take into account the following expressions:

potential energy stired in a capacitor is given by:

U=Q^2/(2*C) where Q and C are the charge and capacitance of the capacitor.

then we have:

Q^2= 2*C*U=

C=εo*A/d where A and d are the area and separation of the parallel plates capacitor

Q^2=2*εo*A*U/d=2*8.85*10^-12*1.9*10^-5*11*10^3/(1.2*10^-3)=

=55.52 *10^-6C

4 0

2 years ago

What is the average time in days between moon phases?.

podryga [215]

Answer:

28

Explanation:

There is a 28 day cycle of the moon phase as it rotates on earths axis.

4 0

1 year ago

Acid rain is the direct result of acid released by burning fossil fuels. T/F

disa [49]

Answer : False.

Explanation : Acid rain is the indirect result of burning fossil fuels. As the incomplete combustion of fossil fuels releases sulfur dioxide and nitrous dioxide in the air. When it rains it gets mixed with water and forms nitric acid and sulfuric acid which causes acid rain. Acid rain is harmful.

7 0

3 years ago

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Two pipes move the same amount of ideal fluid in the same amount of time. One pipe has a 2 in. diameter; the other has a 3 in. d

KATRIN_1 [288]

Answer:

a) 3-in. pipe

Explanation:

Given that

Fluid flow is in same amount in the same time it means that volume flow rate is same for the pipes

Volume flow rate

Q = A V

A=Area ,V=Velocity

$A=\dfrac{\pi}{4}d^2$

If diameter d is more then the velocity will be less for same volume flow rate .We also Know that if pressure is more then the velocity will be less.

The second pipe 3 in diameter having more diameter then the velocity will be less but the pressure will be more.

That is why the 3 in diameter is having more pressure than 2 in diameter pipe.

Therefore the answer will be a.

a) 3-in diameter pipe

6 0

3 years ago

C) Explain the following.Keftles, cooking pans and iron boxes have polished surfaces​

C) Explain the following.Keftles, cooking pans and iron boxes have polished surfaces