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3 years ago

a 0.0780 kg lemming runs off a 5.36 m high cliff at 4.84 m/s. what is its kinetic energy when it's 2.00 m above the ground

Physics

1 answer:

Blababa [14]3 years ago

3 0

Answer:

KE_2 = 3.48J

Explanation:

Conservation of Energy

E_1 = E_2

PE_1+KE_1 = PE_2+KE_2

m*g*h+(1/2)m*v² = m*g*h+(1/2)m*v²

(0.0780kg)*(9.81m/s²)*(5.36m)+(.5)*(0.0780kg)*(4.84m/s)² = (0.0780kg)*(9.81m/s²)*(2m)+KE_2

4.10J+0.914J = 1.53J + KE_2

5.01J = 1.53J + KE_2

KE_2 = 3.48J

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V125BC [204]

Answer:

Current in the toroid will be $I=17.32\times 10^{-3}A$

Explanation:

We have given number of winding in rectangular toroid N = 1500

Self inductance of toroid L = 0.06 H

Magnetic energy stored in toroid $E=9\times 10^{-16}J$

We have to find the current in the toroid

Magnetic energy stored is equal to $E=\frac{1}{2}Li^2$

$9\times 10^{-6}=\frac{1}{2}\times 0.06\times I^2$

$I=17.32\times 10^{-3}A$

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4 years ago

A student is holding a stone at a certain height. The stone has 50 joules of potential energy and 0 joules of kinetic energy. Th

Hitman42 [59]

Answer:

d) The stone will have about 50 joules of kinetic energy and 0 joules of potential energy .

Explanation:

Given :

Initial Potential energy , $P_i=50\ J$ .

Initial Kinetic energy , $K_i=0\ J$ . ( because ball is in rest )

Now , we know , kinetic energy is maximum when an object reaches ground .

Also , potential energy is zero when an object is in ground .

We know , by conservation of energy :

Initial total energy = Final total energy

$P_i+K_i=P_f+K_f\\\\50+0=0+K_f\\\\K_f=50 \ J$

Therefore , option d) is correct .

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3 years ago

What centripetal force is needed to keep a 7kg mass moving in a circle of 4 meters radius at 15m/s

liq [111]

Answer:

We conclude that the centripetal force needed to keep a 7kg mass moving in a circle of 4 meters radius at 15m/s is 393.75 N.

Explanation:

Given

Mass m = 7 kg

Radius r = 4 m

Velocity v = 15m/s

To determine

We need to determine the centripetal force needed to keep a 7kg mass moving in a circle of 4 meters radius at 15m/s.

We know a centripetal force acts on a body to keep it moving along a curved path.

We can determine the centripetal force using the formula

$F_c=\frac{mv^2}{r}$

where

$m$ is the mass

$v$ is the velocity

$r$ is the radius

$F_c$ is the centripetal force

substitute m = 7, r = 4, and v = 15 in the formula

$F_c=\frac{mv^2}{r}$

$F_c=\frac{7\left(15\right)^2}{4}$

$F_c=\frac{1575}{4}$

$F_c=393.75$ N

Therefore, we conclude that the centripetal force needed to keep a 7kg mass moving in a circle of 4 meters radius at 15m/s is 393.75 N.

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3 years ago

The position of an object is given by the equation x = 4.0t2 - 2.0 t - 4.5where x is in meters and t is in seconds. What is the

s344n2d4d5 [400]

Answer:

Explanation:

x = 4 t^2 - 2 t - 4.5

Position at t = 3 s

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v = dx / dt = 8 t - 2

v ( t = 3 s) = 8 x 3 - 2 = 22 m/s

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a = dv / dt = 8

a ( t = 3 s ) = 8 m/s^2

When is the velocity = 0

v = 0

8 t - 2 = 0

t = 0.25 second

When is the position = 0

x = 0

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$t = \frac{2 \pm \sqrt{4 + 72}}{8}$

t = 1.4 second

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3 years ago

What is photoelectric effect

natima [27]

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3 years ago

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