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natka813 [3]
3 years ago
8

A 20 kilogram ball rolls down a 10 meter ramp at the rate of 15 meters per second. The kinetic energy is joules

Physics
1 answer:
kobusy [5.1K]3 years ago
3 0

Answer:2250J

Explanation:

mass(m)=20kg

velocity(v)=15m/s

Kinetic energy=(m x v^2)/2

Kinetic energy =(20 x 15^2)/2

Kinetic energy =(20x15x15)/2

Kinetic energy=4500/2

Kinetic energy=2250J

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An electrical motor spins at a constant 1975.0 rpm. If the armature radius is 7.112 cm, what is the acceleration of the edge of
stealth61 [152]

Answer:

Option D is the correct answer.

Explanation:

Since value of angular acceleration is constant, the body has only centripetal acceleration.

Centripetal acceleration

               a=\frac{v^2}{r}=\frac{(r\omega )^2}{r}=r\omega ^2

We have radius = 7.112 cm = 0.07112 m

Frequency, f = 1975 rpm = 32.92 rps

Angular frequency, ω = 2πf = 2 x π x 32.92 = 206.82 rad/s

Substituting in centripetal acceleration equation,

              a=r\omega ^2=0.07112\times 206.82^2=3042.17m/s^2

Option D is the correct answer.                

3 0
3 years ago
When light propagates from a material with a given index of refraction into a material with a smaller index of refraction, the s
SSSSS [86.1K]

Answer: A) increase

Explanation:

7 0
3 years ago
Superman stops a "speeding locomotive" of mass 8.0x103 kg in 4.0 seconds. If the train was originally moving at 40.m/s,
madreJ [45]

Hello!

<em>a) What is the change in momentum</em>?

The change of the momentum is the velocity, because the velocity is reduced to zero.

We can calculate the aceleration, applicating the formula:

\boxed{a=\frac{V-Vi}{t} }

Like you see, the final velocity will be zero, so:

a = \dfrac{0m/s-40m/s}{4s}

a = \dfrac{-40m/s}{4s}

a = -10\ m/s^{2}

Like you see, the aceleration applicate by superman is of <u>-10 m/s^2.</u>

If the aceleration is negattive, means the velocity will decrease.

<em>b.) What is the magnitud of the force wich superman exerts on the train?</em>

For calculate the force applicate for superman, lets applicate the second law of Newton:

\boxed{F=ma}

Lets replace and resolve it:

F = 8x10^3 kg * (-10 m/s^2)

F = 8000 kg * (-10 m/s^2)

F = -80 000 N

The force applicated is of <u>-80000 Newtons.</u>

When the force is negative means the force applicated in the another direction of the object what is traveling.

8 0
3 years ago
Kelli weighs 440 N, and she is sitting on a playground swing that hangs 0.41 m above the ground. Her mom pulls the swing back an
kifflom [539]

Answer:

Explanation:

Initial height from the ground = .41 m

Final height = 1m

Height by which Kelli was raised ( h )= .59 m

When she passes through the lowest point , she loses P E

= mgh

= 440 x .59

= 259.6 J

kinetic energy possessed by her

= 1/2 mv²

= .5 x (440/9.8) x 2²

= 89.8 J

Difference of energy is lost due to work by  air friction

work done by  friction = 89.8 - 259.6

= - 169.8 J

4 0
3 years ago
The potential of electrons in a circuit can be increased by _____. flowing through the conducting wires the action of a battery
Kaylis [27]
The potential of electrons in a circuit can be increased by the action of a battery.
6 0
3 years ago
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