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3 years ago

What distance will be traveled if you are going 120km/hr for 0.75 hr?

Physics

1 answer:

SVEN [57.7K]3 years ago

5 0

Answer:

60 km

Explanation:

For an object (or a person, such as in this case) moving at constant speed, the speed is equal to the ratio between the distance travelled and the time taken:

where

v is the speed

d is the distance

t is the time taken

In this case, we have:

v = 120 km/h is the speed

t = 30 min = 0.5 h is the time taken

Therefore, we can rearrange the equation to find the total distance travelled:

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The amount of work required for a

kirill [66]

Answer:

if I'm not wrong, 0 Joules

Explanation:

If it is not being moved at all, then no work is being done

8 0

3 years ago

The micrometer (1 μm) is often called the micron. (a) How many microns make up 3.0 km? (b) How many centimeters equal 3.0 μm? (c

Tomtit [17]

Answer:

3 x 10⁻⁹km

3 x 10⁻⁴cm

2.73 x 10⁶μm

Explanation:

A micron is a subunit of measurement usually for length dimensions.

1μm = 1 x 10⁻⁶m

a. How many microns make up 3km;

Now convert to meter first;

1000m = 1km

So, 3km will be made up of 3000m

So;

1 x 10⁻⁶m = 1μm

3000m = $\frac{3000}{1 x 10^{-6} }$ = $\frac{3 x 10^{3} }{ 1 x 10^{-6} }$ = 3 x 10⁻⁹km

b. How many centimeters equal 3.0 μm?

Since;

1μm = 1 x 10⁻⁶m

3μm = 3 x 1 x 10⁻⁶ = 3 x 10⁻⁶m

So;

100cm = 1m;

1m = 100cm

3 x 10⁻⁶m = 3 x 10⁻⁶ x 10² = 3 x 10⁻⁴cm

c. How many microns are in 3.0 yd?

1yd = 0.91m

3yd = 3 x 0.91 = 2.73m

So;

1 x 10⁻⁶m = 1μm

2.73m will give $\frac{2.73}{1 x 10^{-6} }$ = 2.73 x 10⁶μm

3 0

3 years ago

A roundabout is a type of playground equipment involving a large flat metal disk that is able to spin about its center axis. A r

Zina [86]

Answer:

116.1 kgm²/s

1.12718 rad/s

Decreases

Explanation:

m = Mass of girl = 43 kg

M = Mass of roundabout = 120 kg

v = Velocity of roundabout = 2.7 m/s

r = Radius of roundabout = 1 m = R

I = Moment of inertia

Her angular momentum

$L_i=mvr\\\Rightarrow L_i=43\times 2.7\times 1\\\Rightarrow L_i=116.1\ kgm^2/s$

Magnitude of angular momentum is 116.1 kgm²/s

Here the angular momentum is conserved

$L_f=L_i\\\Rightarrow I\omega=L_i\\\Rightarrow (\frac{1}{2}MR^2+mr^2)\omega=116.1\\\Rightarrow \omega=\frac{116.1}{\frac{1}{2}\times 120\times 1^2+43\times 1^2}\\\Rightarrow \omega=1.12718\ rad/s$

Angular speed of the roundabout is 1.12718 rad/s

Initial kinetic energy

$K_i=\frac{1}{2}mv^2\\\Rightarrow K_i=\frac{1}{2}43\times 2.7^2\\\Rightarrow K_i=156.735\ J$

Final kinetic energy

$K_f=\frac{1}{2}I\omega^2\\\Rightarrow K_f=\frac{1}{2}\times (\frac{1}{2}\times 120\times 1^2+43\times 1^2)\times 1.12718^2\\\Rightarrow K_f=65.43253\ J$

The overall kinetic energy decreases as can be seen. This loss is converted to heat.

5 0

3 years ago

On being introduced to the laws of thermodynamics, a student retorted, “When the brakes of a moving car are applied, the kinetic

inn [45]

Answer:

No, not at all. This kinetic energy of car is converted/lost in the form of sound and heat under the tyre when driver apply brakes.

Explanation:

This law states that energy can neither be created nor destroyed but it changes from one form to the other.

In this case reduction of kinetic energy of car does not contradict the law but it changes into heat and sound energy. When driver apply brakes we hear the sound of Tyre due to friction with the road. The tyre become hot too.

So it is not in contradiction to the law of conservation of energy (First Law of Thermodynamics).

Please mark branliest if you are satisfied with the answer. Thanking you in anticipation.

5 0

3 years ago

What is the magnitude of electric field between 2 charged plates that are separated by a distance of 2.4cm, if the voltage acros

Radda [10]

Answer:

V = E * d

E = (200 J/C) / .024 m = 8330 J / C-m

1/2 m v^2 = V q potential energy of electron

v^2 = 2 * 200 J/C * 1.6E-19 C / 9.11 E-31 kg

v^2 = 400 * 1.6E-19 / 9.11 E-31 N-m / kg

v = 8.4E6 m/s

7 0

2 years ago