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lorasvet [3.4K]
2 years ago
15

A moving car initially has kinetic energy K. The car then moves in the opposite direction with four times its initial speed. Wha

t is the kinetic energy now
Physics
1 answer:
Liula [17]2 years ago
6 0

If initial speed was v, Kinetic energy was K = 1/2mv^2

When speed will be 4v, KE will be:

= 1/2 m (4v)^2

=1/2m 16 v^2

=16K

Now kinetic energy will become <em>1</em><em>6</em><em> </em><em>times</em><em> </em><em>of</em><em> </em><em>initial</em><em> </em><em>Kinetic</em><em> </em><em>Energy</em>

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you want to describe the harmonic motion of a swing. you find out that it takes 2 seconds for the swing to complete one cycle. w
7nadin3 [17]
If it takes the swing 2 seconds to complete one cycle, then
that's the period of its motion ... 2 seconds.

The frequency is the reciprocal of the period ... 1/2 Hz.
('Hz' means 'per second'.)
4 0
2 years ago
The speed of light is about 3.00 × 105 km/s. It takes approximately 1.28 seconds for light reflected from the
Ulleksa [173]
Just to correct you - the speed of light is 3.0 x 10^5 km/sec and not 105 km/sec as given by you (maybe it was just a typing mistake from your end).

The average distance between earth and moon would be - 384,000 kms. 

This is calculated by the formula -> Distance = Speed x Time.
 

8 0
2 years ago
A 20 kg wagon is pulled along the level ground by a rope inclined at 30 degree above the horizontal. A friction force of 30 N op
Elan Coil [88]

(a) 34.6 N

To solve the problem, we have to analyze the forces acting along the horizontal direction.

We have:

- Forward: the component of the pull parallel to the ground, which is

F cos \theta

where

F is the magnitude of the pull

\theta=30^{\circ} is the angle

- Backward: the force of friction, which is

F_f = 30 N

So, the equation of motion is

F cos \theta - F_f = ma

where

m = 20 kg is the mass of the wagon

a is the acceleration

In this part, the wagon is moving at constant speed, so a =0 and the equation becomes

F cos \theta - F_f = 0

Therefore, we can find the pulling force:

F=\frac{F_f}{cos \theta}=\frac{30}{cos 30}=34.6 N

(b) 43.9 N

In this case, the acceleration is

a=0.40 m/s^2

So, the equation of motion in this case is

F cos \theta - F_f = ma

So this time we have to take into account the term (ma).

Using the  same data as before:

m = 20 kg

\theta=30^{\circ}

F_f = 30 N

We find the new magnitude of F:

F=\frac{ma+F_f}{cos \theta}=\frac{(20)(0.40)+30}{cos 30}=43.9 N

6 0
2 years ago
Determine the resultant moment of the forces acting about the x, y, and z axes. Suppose that f1 = 200 n, f2 = 60 n, f3 = 115 n,
SpyIntel [72]

Based on the forces acting on the axes, the resultant moments will be (345, 400, 600 N·m)

<h3>What would be resultant moment about x-axis?</h3>

= F₃ x 3

= -115 x 3

= -345 N·m

<h3>What would be resultant moment about y-axis?</h3>

= F₁ x 2

= -200 x 2

= -400 N·m

<h3>What would be the resultant moment about z-axis?</h3>

= F₄ x 2

= -300 x 2

= - 600 N·m

In conclusion, the resultant moment about x, y, and z axes is (345, 400, 600 N·m)

Find out more on resultant moments at brainly.com/question/6278006.

5 0
2 years ago
An earthquake is a natural rapid shaking of the _______ caused by the release of stored energy in rocks
REY [17]

Answer:

An earthquake is a natural rapid shaking of the tectonic plates caused by the release of stored energy in rocks

Explanation:

there are tectonic plates and the earthquake is caused by that energy the plates are always moving so it might get stuck in between each other and store the energy.

8 0
2 years ago
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