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1 year ago

14

Which dog has the most kinetic energy? A. A dog of mass 12 kg running with speed 6 m/s B. A dog of mass 10 kg running with speed

3 m/s C. A dog of mass 16 kg running with speed 5 m/s D. A dog of mass 14 kg running with speed 4 m/s

1 answer:

Nonamiya [84]1 year ago

5 0

Answer:

A

Explanation:

KE = 1/2 m v^2

the greatest is A

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Help me pls, the lesson is simple machines

Y_Kistochka [10]

Answer:

1.pulley,screw,inclined plane

2.using simple machine properly with right way and precautions

Explanation:

3.cuz if they are not used properly they can cause injuries to organs

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2 years ago

2. A boy pushes forward a cart of groceries with a total mass of 45.0 kg. What is the

likoan [24]

Answer:

A aceleração do carrinho é de, aproximadamente, 1,46 m/s².

Explanation:

F=ma

F: force

m: mass

a: aceleration

66 = 45a

a=66/45= 22/15 ≅ 1,4666 m/s²

4 0

2 years ago

Read 2 more answers

The momentum of an electron is 1.75 times larger than the value computed non-relativistically. What is the speed of the electron

FrozenT [24]

Answer:

<em>Speed of the electron is 2.46 x 10^8 m/s</em>

<em></em>

Explanation:

momentum of the electron before relativistic effect = $M_{0} V$

where $M_{0}$ is the rest mass of the electron

V is the velocity of the electron.

under relativistic effect, the mass increases.

under relativistic effect, the new mass M will be

M = $M_{0}/ \sqrt{1 - \beta ^{2} }$

where

$\beta = V/c$

c is the speed of light = 3 x 10^8 m/s

V is the speed with which the electron travels.

The new momentum will therefore be

==> $M_{0}V/ \sqrt{1 - \beta ^{2} }$

It is stated that the relativistic momentum is 1.75 times the non-relativistic momentum. Equating, we have

1.75 $M_{0} V$ = $M_{0}V/ \sqrt{1 - \beta ^{2} }$

the equation reduces to

1.75 = $1/ \sqrt{1 - \beta ^{2} }$

square both sides of the equation, we have

3.0625 = 1/ $(1 - \beta ^{2} )$

3.0625 - 3.0625 $\beta ^{2}$ = 1

2.0625 = 3.0625 $\beta ^{2}$

$\beta ^{2}$ = 0.67

β = 0.819

substitute for $\beta = V/c$

V/c = 0.819

V = c x 0.819

V = 3 x 10^8 x 0.819 = <em>2.46 x 10^8 m/s</em>

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3 years ago

At the same temperature, two wires made of pure copper have different resistances. The same voltage is applied at the ends of ea

Semmy [17]

Answer:

Explanation:

As we know that the resistance of the wire is directly proportional to the length of wire and inversely proportional to the area of crossection of the wire.

As the material is copper for both the wires so the resistivity is same and the voltage is also same. As their resistance is different it means either length is different or the area of crossection is different.

6 0

3 years ago

A person is trying to lift a crate that has a mass of 30 kg. The normal force of the floor is currently supplying 150N of force.

alexdok [17]

Here when an object is placed on the level floor then in that case there are two forces on the object

1). Weight of object downwards (mg)

2). Normal force due to floor which will counterbalance the weight (N)

so when no force is applied on the box at that time normal force is counter balanced by weight.

Now here it is given that A person tried to lift the box upwards

So now there are two forces on the box

1). Applied force of person

2). Normal force due to ground

So now these two forces will counter balance the weight of the crate

So we can write an equation for force balance like

$F_g = F_n + F_a$

given that

$F_g = mg$

here

m = 30 kg and

g = acceleration due to gravity = 10 m/s^2

$F_n = 150 N$

now from above equation

$30*10 = 150 + F_a$

$F_a = 300 - 150 = 150 N$

So force applied by the person must be 150 N

7 0

3 years ago