PHYSICS MIDDLE SCHOOL

(please show work)A rock is dropped off of a cliff. It falls to the ground in 10 seconds. Answer the following questions assuming that there is no air resistance.


c. What is the instantaneous velocity of the rock just before it hit the ground?


d.Find the rock's displacement for the 10 seconds.​
(please show work) A rock is dropped off of a - 1

Answers

Answer 1
Answer:

c. -98 m/s

The motion of the rock is a uniformly accelerated motion (free fall) with constant acceleration g=-9.8 m/s^2 (negative since it is downward). Therefore, we  can find its velocity using the following suvat equation

v=u+gt

where

v is the final velocity

u is the initial velocity

g is the acceleration of gravity

t is the time

For the rock in the problem,

u = 0

So, its velocity at t = 10 s is

v=0+(-9.8)(10)=-98 m/s

where the negative sign indicates that the velocity points downward.

d. -490 m

Since the motion is at constant acceleration, we can use another suvat equation:

s=ut+(1)/(2)gt^2

where

s is the displacement

u is the initial velocity

g is the acceleration of gravity

t is the time

Substituting:

u = 0

g=-9.8 m/s^2

t = 10 s

We find the rock's displacement:

s=0+(1)/(2)(-9.8)(10)^2=-490 m

where the negative sign means the displacement is downward.

Related Questions

Could someone please explain what makes up the electromagnetic spectrum? Thank you.
What is cell division? Like what does it mean? And also if you know, what does it do? Like what's the purpose of it. THANKSSS!!!!!
Explain why atmospheric pressure changes as atmospheric depth changes.
Which parts of the graph would increase if all of earth's polar ice melts? Which part would decrease?
How do you know an object is in motion?a. it has inertiab. it has massc. it is changing positiond. it has a reference point

A force that causes an object to change its motion is called a(n) _______a. unbalanced force
b. resistant force
c. compound force
d. unnatural force

Answers

Unbalanced force causes an object to change its motion.

Answer: Option A

Explanation:

A force can be explained as push or a pull that has the tendency to change the velocity of a mass.

The force that makes any change in the movement of an object or body is known to be an unbalanced force. These forces are not equal and opposite. When an object is placed in a rest position and when unbalanced force acts on it, this will not make the object to move.

Example: Force applied against the ball.

The forces whose size is equal and opposite in their direction are known as balanced force. These forces will not make any change in motion of a body. When an object is placed in a rest position and when balance force acts on it, this will not make the object to move.

Example: Pushing against a wall.  

Answer:

I believe it is A. Unbalanced.

Explanation:

Hope i helped you!

7. Alice holds a black belt in Taekwondo and her fist has a mass of 0.5 kg. Her fist obtains a velocity of 5 m/s in 0.1 seconds from rest. Evaluate the average net force applied to the fist.

Answers

Answer: 25 N

Explanation:

the fist hit by the black belt Alice in the Taekwondo has been given to have a mass of 0.5 kg which acquires a velocity of 5 m/s in a time of 0.1 sec, therefore, the average net force which is being applied to the fist can be calculated by the following method,

Given,   mass m=0.5 kg, velocity v=5 m/s, time t=0.1 sec

As we know that, acceleration

a=(v-u)/(t)=(5-0)/(0.1)=50 \mathrm{m} / \mathrm{s}^(2)

Thereby,

\text { Force }=\text { mass } * \text { acceleration }=0.5 * 50=25 N

Answer:

25N

Explanation:

Find acceleration first

A=v-u/t

acceleration = 5/0.1s =50m/s^2

then find net force using f=mass x acceleration, which iin this case is 25N

Need help on science please!

Answers

Fossil fuels are formed when dead, buried, and decomposing organisms are compressed under extreme pressure and heat for millions of years. We need other sources of fuel today... strictly speaking you don't. But if we hold off developing alternatives until the fossil fuels truly run out, then there will be absolute chaos getting the new ones available. Thats all i got

The amount of water vapor in the air is known as the _______.a.temperature b.condensation c.humidity d.precipitation

Answers

it is C the humidity
The amount of water vapor in the air is known as the _______.

c. Humidity

A horse runs around a circular track that is 350.0 m long. He runs clockwise fromthe start line back to the start line, then turns back and goes counterclockwise back
to the start line again. What is the horses displacement?

A. 0 m
B. 300.0 m counterclockwise
C. 300.0 m counterclockwise
D. 600.0 m

Answers

Answer:

A 0m

Explanation:

The horse runs clockwise round the strack, then goes back to the start line ending up back at the same place when it started.
A. 0

As the horse goes back to the same “start line”.

8 Explain How can subsidence lead to the formation of sedimentary rock

Answers

the water runs out the holler and through the creek an then the molecules sedimentate
Other Questions
A certain location is experiencing severe tornadoes for several days. Which of the following should happen in the location?A-People should stay indoors and seek shelter.B-All radios and televisions should be switched offC-People should rush to the highest floor of their housesD-All doors and windows should be kept open for easy exit.
A box weighing 100 newtons is pushed up an inclined plane that is 5 meters long. It takes a force of 75 newtons to push it to the top, which has a height of 3 meters. What is the efficiency?
Why AA batteries run exactly 1.5V?
Which of the following describes the energy transformation that takes place when a boy eats an apple and then lifts weights?1. Chemical energy is converted to mechanical and heat energy. 2.Chemical energy is converted to mechanical energy. 3. Chemical energy is converted to heat energy. 4. Chemical energy is converted to mechanical and kinetic energy.