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3 years ago

A 3 kg rock sits on a 0.8 meter ledge. If it is pushed off, how fast will it be going at the bottom?

1 answer:

andrey2020 [161]3 years ago

6 0

As long as it sits on the shelf, its potential energy
relative to the floor is . . .

   Potential energy =    (mass) x (gravity) x (height) =

   (3 kg) x (9.8 m/s²) x (0.8m) = <u>23.52 joules</u> .

If it falls from the shelf and lands on the floor, then it has exactly that
same amount of energy when it hits the floor, only now the 23.52 joules
has changed to kinetic energy.

   Kinetic energy =    (1/2) x (mass) x (speed)²

   23.52 joules = (1/2) x (3 kg) x (speed)²

Divide each side by 1.5 kg :    23.52 m²/s² = speed²

Take the square root of each side: speed = √(23.52 m²/s²) = <em>4.85 m/s </em> (rounded)

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Which statement describes how the atoms in a conducting wire are organized?(1 point)

yulyashka [42]

Answer:

Positively charged nuclei are packed in an organized pattern, and the negatively charged valence electrons flow freely.

Explanation:

3 0

2 years ago

How much will the kinetic energy of a school bus increase if its velocity is tripled?

son4ous [18]

Answer:

Explanation:

Given a school bus.

Let say initially the school bus is traveling with speed "v"

Let assume mass of school bus is "m"

Then, the initial kinetic energy is

K.E_initial = ½mv²

Now, if the initial velocity is tripled,

Then, the new velocity is

v_new = 3v.

Note: the mass of the school does not change it is constant

Then, new kinetic energy is

K.E_new = ½m(v_new)²

v_new = 3v

Then,

K.E_new = ½m(3v)²

K.E_new = ½m × 9v²

K.E_new = 9 × ½mv²

Since K.E = ½mv²

Then,

K.E_new = 9 × K.E

So, the new kinetic energy will be 9 times the initial kinetic energy.

So, option D is correct

D. It will be nine times greater.

4 0

3 years ago

An object is observed for a time interval of 20 seconds. From time 6.7 s the object experiences a Force of 106 N that lasts unti

shusha [124]

Answer:

1654 kg m/s

Explanation:

The impulse experienced by an object is equal to the product between the force exerted on the object and the time during which the force lasts:

$I=F\Delta t$

where:

I is the impulse

F is the force exerted on the object

$\Delta t$ is the time during which the force is applied

For the object in this problem, we have

$F=106 N$ (force applied)

$\Delta t= 15.6 s$ (time interval)

Therefore, the impulse experienced by the object is:

$I=(106)(15.6)=1654 kg m/s$

3 0

2 years ago

A 1100 kg car starts from rest and accelerates for 5 seconds at 4.6m/s/s how much power does the car generate

SIZIF [17.4K]

Answer:

The power expended by the car during the acceleration is 116.38KW

Explanation:

Power is a term that defines the rate at which energy is expended whenever work is done.

Power can be given as Force X velocity.

Force can be found using the formula:

F = mass X acceleration.

In this case,

F = 1100kg X 4.6m/s2

F = 5060 N

The final velocity, v of the car can be obtained from this formula:

v = u+ at

U = initial velocity = 0 (since the car started from rest)

a = acceleration = 4.6m/s2

t = time = 5 seconds

v = 0 + 4.6 X 5 = 23 m/s

Therefore, the power expended is 5060N X 23m/s=116,380W

The power expended by the car during the acceleration is 116.38KW

3 0

2 years ago

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ikadub [295]

$\sf \huge \purple{ Question : - }$

Initial velocity of a car is 36 km/h . Find the distance after min, if it goes with acceleration 2 m/s².

$\sf \huge \color {gold}{ AnSwer :- }$

Initial velocity, u = 36 km/h

$\sf u = 36 \times \dfrac{5}{18} {ms}^{ - 1} = 10 {ms}^{ - 1}$

Time, t = 1min

t = 60s

Acceleration, a = 2m/s²

Apply 2nd equation of motion

$\longrightarrow \sf s = ut + \dfrac{1}{2} at ^{2} \\ \\ \longrightarrow \sf s =(10)(60) + \frac{1}{2} (2)(60) {}^{2} \\ \\ \longrightarrow \sf s =600 + 3600 \\ \\ \longrightarrow \sf \blue{ s =4200m} \: \: \large \blue \star$

6 0

3 years ago