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tigry1 [53]
3 years ago
15

A student throws a rock horizontally from the edge of a cliff that is 20 m high. The rock has an initial speed of 10 m/s. If air

resistance is negligible, the distance from the edge of the base of the cliff to where the rock hits the level ground below the cliff is most nearly
a. 20 m

b. 5 m

c. 10 m

d. 40 m
Physics
1 answer:
Gwar [14]3 years ago
8 0

Answer:

option A

Explanation:

given,

height of the cliff = 20 m

initial speed = 10 m/s

distance from the edge of the base of the cliff  = ?

now,

time taken to cover vertical distance

initial vertical speed = 0 m/s

using equation of motion

s = u t + \dfrac{1}{2}gt^2

s =\dfrac{1}{2}gt^2

t = \sqrt{\dfrac{2s}{g}}

t = \sqrt{\dfrac{2\times 20}{9.8}}

  t = 2 s

in same time the ball will travel horizontal distance

horizontal velocity of ball = 10 m/s

distance = s x t

d = 10 x 2

d = 20 m

Hence, the correct answer is option A

You might be interested in
A merry-go-round with a a radius of R = 1.63 m and moment of inertia I = 196 kg-m2 is spinning with an initial angular speed of
kondor19780726 [428]

Answer:

1) L = 299.88 kg-m²/s

2) L = 613.2 kg-m²/s

3) L = 499.758 kg-m²/s

4) ω₁ = 0.769 rad/s

5) Fc = 70.3686 N

6) v = 1.2535 m/s

7) ω₀ = 1.53 rad/s

Explanation:

Given

R = 1.63 m

I₀ = 196 kg-m²

ω₀ = 1.53 rad/s

m = 73 kg

v = 4.2 m/s

1) What is the magnitude of the initial angular momentum of the merry-go-round?

We use the equation

L = I₀*ω₀ = 196 kg-m²*1.53 rad/s = 299.88 kg-m²/s

2) What is the magnitude of the angular momentum of the person 2 meters before she jumps on the merry-go-round?

We use the equation

L = m*v*Rp = 73 kg*4.2 m/s*2.00 m = 613.2 kg-m²/s

3) What is the magnitude of the angular momentum of the person just before she jumps on to the merry-go-round?

We use the equation

L = m*v*R = 73 kg*4.2 m/s*1.63 m = 499.758 kg-m²/s

4) What is the angular speed of the merry-go-round after the person jumps on?

We can apply The Principle of Conservation of Angular Momentum

L in = L fin

⇒ I₀*ω₀ = I₁*ω₁

where

I₁ = I₀ + m*R²

⇒  I₀*ω₀ = (I₀ + m*R²)*ω₁

Now, we can get ω₁

⇒  ω₁ = I₀*ω₀ / (I₀ + m*R²)

⇒  ω₁ = 196 kg-m²*1.53 rad/s / (196 kg-m² + 73 kg*(1.63 m)²)

⇒  ω₁ = 0.769 rad/s

5) Once the merry-go-round travels at this new angular speed, with what force does the person need to hold on?

We have to get the centripetal force as follows

Fc = m*ω²*R  

⇒  Fc = 73 kg*(0.769 rad/s)²*1.63 m = 70.3686 N

6) Once the person gets half way around, they decide to simply let go of the merry-go-round to exit the ride.

What is the linear velocity of the person right as they leave the merry-go-round?

we can use the equation

v = ω₁*R = 0.769 rad/s*1.63 m = 1.2535 m/s

7) What is the angular speed of the merry-go-round after the person lets go?

ω₀ = 1.53 rad/s

It comes back to its initial angular speed

8 0
3 years ago
Explain the relationship between electrical charge and force.
Radda [10]
The relationship between electrical and charge force is that electrical force strengthens and increases the energy pulses and reflects off an object and makes the force about two times greater with charge.
7 0
2 years ago
Color depends on what characteristic of light?
Andrej [43]

Answer:

On the wavelength

Explanation:

Visible light is just a small portion of the electromagnetic spectrum, which classifies all the electromagnetic waves from shortest wavelength (gamma rays) to longest wavelength (radio waves).

Visible light refers to the part of the spectrum which has wavelength between 380 nm and 750 nm. These are the only electromagnetic wave that our eyes can see, and depending on their wavelength, they appear as a different color. In particular, each color corresponds to a different range of wavelengths:

Violet: 380-450 nm

Blue: 450-495 nm

Green: 495-570 nm

Yellow: 570-590 nm

Orange: 590-620 nm

Red: 620-750 nm

6 0
3 years ago
Two students were climbing stairs at school. Student 1 has a weight of 700 N. Student 2 has a weight of 650 N. How much power wo
KIM [24]

Student 1 would have a power 467 W and student 2 would have a power of 433 W. The correct option is the fourth option - Student 1 would have 467 W, and Student 2 would have 433 W of power.

From the question,

We are to calculate the power each student would have to climb the flight of stairs.

Power can be calculated using the formula

P = \frac{F \times d}{t}

Where

P is Power

F is the force

d is the distance

and t is the time

NOTE: The weight of the students represent the force

  • For student 1

F = 700 N

d = 4 m

t = 6 s

∴ P = \frac{700 \times 4}{6}

P = 467 W

  • For student 2

F = 650 N

d = 4 m

t = 6 s

∴ P = \frac{650 \times 4}{6}

P = 433 W

Hence, Student 1 would have a power 467 W and student 2 would have a power of 433 W. The correct option is the fourth option - Student 1 would have 467 W, and Student 2 would have 433 W of power.

Learn more here: brainly.com/question/18801566

3 0
2 years ago
You use a pulley system to lift a car engine. You apply a force of 120n and the pulley pulls on the engine with a force of 1050n
Savatey [412]

Given,

Effort force = 120 N

Load force= 1050 N

Mechanical advantage of a pulley is given by the ratio of load force to the effort force.

M.A=\frac{Load force}{Effort force}

=\frac{1050}{120}

=8.75

Therefore, the mechanical advantage of the given pulley is 8.75.

5 0
3 years ago
Read 2 more answers
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