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3 years ago

This is a sience question

Physics

2 answers:

coldgirl [10]3 years ago

4 0

A is the right answer

levacccp [35]3 years ago

3 0

I would say A is the answer im not sure tho

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A 3.0-kg block starts at rest at the top of a 37° incline, which is 5.0 m long. Its speed when it reaches the bottom is 2.0 m/s.

Mama L [17]

Answer: $f_{r}$ = 16.49N

Explanation: The object is placed on an inclined plane at an angle of 37° thus making it weight have two component,

$W_{x}$ = horizontal component of the weight = mgsinФ

$W_{y}$ = vertical component of weight = mgcosФ

Due to the way the object is positioned, the horizontal component of force will accelerate the object thus acting as an applied force.

by using newton's law of motion, we have that

mgsinФ - $f_{r}$ = ma

where m = mass of object=5kg

a = acceleration= unknown

Ф = angle of inclination = 37°

g = acceleration due to gravity = 9.8 $m/s^{2}$

$f_{r}$ = frictional force = unknown

we need to first get the acceleration before the frictional force which is gotten by using the equation below

$v^{2} = u^{2} + 2aS$

where v = final velocity = 2m/s

u = initial velocity = 0m/s (because the object started from rest)

a= unknown

S= distance covered = length of plane = 5m

$2^{2} = 0^{2} + 2*a*5\\\\4= 10 *a\\\\a = \frac{4}{10} \\a = 0.4m/s^{2}$

we slot in a into the equation below to get frictional force

mgsinФ - $f_{r}$ = ma

3 * 9.8 * sin 37 - $f_{r}$ = 3* 0.4

17.9633 - $f_{r}$ = 1.2

$f_{r}$ = 17.9633 - 1.2

$f_{r}$ = 16.49N

4 0

3 years ago

In a pendulum system, when is it possible for the potential and kinetic energies both to be equal to zero

muminat

That's ONLY true when the pendulum is hanging
in the center position and not moving.

8 0

3 years ago

Why does a plastic comb attract small bits of paper after rubbing with wool?

navik [9.2K]

Static electricity. Like the balloon against hair

5 0

3 years ago

A radio station's channel, such as 100.7 fm or 92.3 fm, is actually its frequency in megahertz (mhz), where 1mhz=106hz. calculat

lakkis [162]

When it comes to wave behavior, there are parameters called wavelength and frequency. These two are related by speed of the radiowave. Radiowaves are electromagnetic waves which travels as fast as light. The wavelength is the distance while frequency is the reciprocal of time. When you multiply them both, you get the electromagnetic wave's speed. The equation is c = wavelength*frequency, where c is the speed of light equal to 3 x 10^8 m/s.

3 x10^8 m/s = wavelength/104.9 x 10^6 Hz (Hertz is 1/s)
wavelength = 2.86 meters

6 0

3 years ago

If a 54 kg sprinter can accelerate from a standing start to a speed of 10 m/s in 3 s, what average power is generated?

lora16 [44]

Answer:

Power, P = 600 watts

Explanation:

It is given that,

Mass of sprinter, m = 54 kg

Speed, v = 10 m/s

Time taken, t = 3 s

We need to find the average power generated. The work done divided by time taken is called power generated by the sprinter i.e.

$P=\dfrac{W}{t}$

Work done is equal to the change in kinetic energy of the sprinter.

$P=\dfrac{\dfrac{1}{2}mv^2}{t}$

$P=\dfrac{\dfrac{1}{2}\times 54\ kg\times (10\ m/s)^2}{3\ s}$

P = 900 watts

So, the average power generated by the sprinter is 900 watts. Hence, this is the required solution.

3 0

3 years ago