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3 years ago

The kinetic energy of a car of mass 180kg moving at a constant velocity is 4410J. What is its velocity?

Physics

1 answer:

Delvig [45]3 years ago

5 0

Answer:

7m/s

Explanation:

Data obtained from the question include:

K.E (kinetic energy) = 4410J

m (mass) = 180kg

V (velocity) =?

Kinetic energy is the energy an object possess while in motion. It is represented mathematically as:

K.E = 1/2 mv^2

With the above formula, we obtained the velocity the car as follow:

K.E = 1/2mv^2

4410 = 1/2 x 180 x v^2

4410 = 90 x v^2

Divide both side by 90

v^2 = 4410/90

v^2 = 49

Take the square root of both side

v = √49

v = 7m/s

Therefore, the velocity of the car is 7m/s

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Suppose that you are swimming in a river while a friend watches from the shore. In calm water, you swim at a speed of 1.25 m/s .

aliya0001 [1]

Answer: The observing friend will the swimmer moving at a speed of 0.25 m/s.

Explanation:

Let <em>S</em> be the speed of the swimmer, given as 1.25 m/s

Let $S_{0}$ be the speed of the river's current given as 1.00 m/s.

Note that this speed is the magnitude of the velocity which is a vector quantity.

The direction of the swimmer is upstream.

Hence the resultant velocity is given as, $S_{R}$ = S — S 0 $S_{0}$

$S_{R}$ = 1.25 — 1

$S_{R}$ = 0.25 m/s.

Therefore, the observing friend will see the swimmer moving at a speed of 0.25 m/s due to resistance produced by the current of the river.

6 0

3 years ago

A light bulb dissipates 100 Watts of power when it is supplied a voltage of 220 volts.

ycow [4]

Given Information:

Power = P = 100 Watts

Voltage = V = 220 Volts

Required Information:

a) Current = I = ?

b) Resistance = R = ?

Answer:

a) Current = I = 0.4545 A

b) Resistance = R = 484 Ω

Explanation:

According to the Ohm’s law, the power dissipated in the light bulb is given by

$P = VI$

Where V is the voltage across the light bulb, I is the current flowing through the light bulb and P is the power dissipated in the light bulb.

Re-arranging the above equation for current I yields,

$I = \frac{P}{V} \\\\I = \frac{100}{220} \\\\I = 0.4545 \: A \\\\$

Therefore, 0.4545 A current is flowing through the light bulb.

According to the Ohm’s law, the voltage across the light bulb is given by

$V = IR$

Where V is the voltage across the light bulb, I is the current flowing through the light bulb and R is the resistance of the light bulb.

Re-arranging the above equation for resistance R yields,

$R = \frac{V}{I} \\\\R = \frac{220}{0.4545} \\\\R = 484 \: \Omega$

Therefore, the resistance of the bulb is 484 Ω

3 0

2 years ago

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The first PCS technology used a form of time division multiplexing called ____. a. Time Division Multiple Access (TDMA) b. Gl

salantis [7]

Answer:

A. Time Division multiple Access (TDMA)

Explanation:

Time-division multiple access (TDMA) is a channel access method for shared-medium networks

It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot.

3 0

2 years ago

A team of eight dogs pulls a sled with waxed wood runners on wet snow (mush!). The dogs have average masses of 18.5 kg, and the

meriva

Answer:

a. $2.86 m/s^2$

b.1058 N

Explanation:

We are given that

Mass of each dog,M=18.5 kg

Mass of sled with rider,m=250 kg

a.Average force,F=185 N

$\mu_s=0.14$

$g=9.8 m/s^2$

By Newton's second law

$8F-f=(8M+m)a$

$a=\frac{8F-f}{8M+m}=\frac{8(185)-(0.14)(9.8)(250)}{8(18.5)+250}$

$a=2.86 m/s^2$

b.By Newton's second law

$T=ma+\mu_s mg$

Substitute the values

$T=250\times 2.86+0.14(250)(9.8)=1058 N$

Hence, the force in the coupling between the dogs and the sled=1058 N

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3 years ago

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elena-s [515]

Answer:

Explanation:

5 0

2 years ago

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