The potential energy of the rock is 19600 J. Then, the kinetic energy when it hits the ground will be 19600 J. The velocity before it hits the ground will be 44.2 m/s.
What is potential energy ?The potential energy of an object is the energy by virtue of its position. It is related to the mass, m ,height h and acceleration due to gravity g as follows:
p = mgh.
Given m =20 kg
height = 100 m
g = 9.8 m/s²
then p = 20 kg × 100 m × 9.8 m/s² = 19600 J.
When the rock falls down as it approaches the ground, the potential energy converts to kinetic energy. Hence, the kinetic energy before it strike the ground will be 19600 J.
Ke = 1/2 mv² = 19600 J
then v = √ (2 Ke/m)
v = √(2× 19600 J/20 kg) = 44.2 m/s.
Therefore, the speed of the rock as it hits the ground is 44.2 m/s.
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A bag of frozen vegetables expanding in the microwave is a good example of how volume __________.
A. increases when temperature decreases
B. decreases when temperature increases
C. decreases when temperature decreases
D. increases when temperature increases
Answer:
D
Explanation:
because when the temperature increases things tend to rise and explode instead of decreasing
A generator is operating with 5% droop primary control. The generator is rated for 100 kW. Its secondary power command at this point in time (in other words, the power commanded to produce at 60 Hz) is 67 kW. The grid frequency is currently 59.9 Hz. What is the generator power
The generator power will be 59 kW. Power drop is the main factor for finding the generated power.
What is the power rating?The maximum power input allowed to pass through a piece of equipment is known as the equipment's power rating.
Power drop = 5%
The relation of the frequency change with the power drop is;
[tex]\rm \frac{df}{dp} =5\%\\\\ \frac{f_{rated-f_1}}{P_{rated}-P_1}=0.05\\\\ \frac{f_{rated-60}}{100-61}=0.05\\\\ f_{rated}=61.95[/tex]
For the grid frequency, 59.9 Hz
[tex]\rm \frac{f_{rated-f_2}}{P_{rated}-P_2}=0.05[/tex]
[tex]\rm \frac{61.95-f_2}}{100-P_2} =0.05\\\\ 100-P_2 =20(61.95-59.9)\\\\P_2=100-41 \\\\ P_2=59 \ kW[/tex]
Hence, the generator power will be 59 kW.
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Let each shake of the pennies or thumbtacks represent 1 year. what is the half life, in years, for the pennies in experiment 1? what is the half-life, in years, for the thumbtacks in experiment 2?
(5.4.3 lab - nuclear physics)
The half-life of the pennies in experiment 1 and 2 will be the time it takes for half the pennies to fall off after shaking.
What is Half-Life?Half-Life is the time required for half the amount one a given substance to disappear or decay.
The half-lives of substances are usually constant values.
For example, the Half-Life of radioactive carbon-14 is 5700 years.
Therefore, the half-life of the pennies in experiment one and two will be the time it takes for half the pennies to fall off after shaking.
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Question 12 (True/Faise Worth 5 points)
The presence of free electrons makes a material a good insulator.
O True
O False
When two forces act in the same direction on an object, the net force is found by ....................the forces.
Answer:
Net force is found by sum of the forces.
Answer:
The correct answer is When two forces act in the same direction on an object, the net force is found by the sum of the forces.
Hope this helps you!!
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Thankyou for joining Brainly communicty!!!Tyra pushes the pedals of her bicycle with her feet to make it go faster. Which of Newton's laws is demonstrated by this action
The impressed force increases when Tyra pushes the pedals of her bicycle, the momentum of the bike increases hence it moves faster.
What are the laws of motion?The Newton's laws of motion lay the foundation for dynamics. According to Newton's second law, the rate of change of momentum is directly proportional to the impressed force.
Hence, as the impressed force increases when Tyra pushes the pedals of her bicycle, the momentum of the bike increases hence it moves faster.
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Explore the role of friction when creating safety ramps and escalators. "Why is it important for people and object to move slowly on ramps and escalator?
The role of friction is of great importance when creating safety ramps and escalators because with the help of friction things move.
Why is it important to move objects slowly on ramps and escalator?It is important to move objects slowly on ramps and escalator because the ramps and escalator moves object in the opposite direction of gravity. If we did not move objects slowly, then the objects or a person get damaged.
So we can conclude that the role of friction is of great importance when creating safety ramps and escalators because with the help of friction things move.
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Describe the electric and magnetic fields of an electromagnetic wave.
Answer:The electric field and magnetic field of an electromagnetic wave are perpendicular (at right angles) to each other. They are also perpendicular to the direction of the EM wave. EM waves travel with a constant velocity of 3.00 x 108 ms-1 in vacuum.
Explanation:
The coefficient of dynamic friction between the grass and a 200 kg football blocking sled is 0.20. If a football player only pushes horizontally against the sled, how large must the horizontal force be to keep the sled moving at constant velocity
The horizontal force be to keep the sled moving at constant velocity is 392 N.
Horizontal force applied to the sled
The horizontal force applied to the sled to prevent it from moving is calculated from Newton's second law of motion.
F - Ff = ma
where;
a is acceleration of the sledat constant velocity, a = 0
F - μmg = m(0)
F - μmg = 0
F = μmg
F = 0.2 x 200 x 9.8
F = 392 N
Thus, the horizontal force be to keep the sled moving at constant velocity is 392 N.
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Adrian plays basketball with Kevin on a basketball court that is completely level. After Adrian makes as basket, their ball rolls to a complete stop. what forces acted on the ball to cause it to stop rolling?
A. acceleration and gravity
B. friction and acceleration
C. gravity and friction
D. magnetic forces and friction
The long structure of small intestine is accommodated in small space within our body. Comment.
Help me pleaseee
a battery-operated toy draws 0.2 a of current from a battery pack. if the total resistance
of the boy is 362, what is the voltage of the battery pack?
A nuclear power plant is built alongside a river. what measurements should a monitoring station downstream record to be sure that the proper procedures are being followed at the power plant? density and radiation levels radiation levels and dust levels salt concentration and temperature temperature and radiation levels
Nuclear power plant should have monitoring units and water purifiers units, so thet they followed propress in the plant.
What is nuclear power plant?
Nuclear power plant is a structure that allows the generation of energy from the fission of toxic materials. It is usually due to the risk of accidents. Nuclear energy is very important for the generation of electricity in many countries.
Hence, water purifiers units should be used in the downstream to measure to protect river should be taken.
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Answer:
temperature and radiation levels
Explanation:
edge
Show the molecular formula and electron structure of the simplest compound that forms with only carbon and hydrogen atoms.
The simplest compound of hydrocarbon is methane
The formula is CH_4It belongs to alkane group and has single bonds.The electron structure attached
What was the stated reason why Red Bull Stratos mission executed?
A.
Red Bull wanted a publicity stunt that caught the eye of consumers.
B.
A new one-manned capsule was invented and needed to use a human as its test pilot.
C.
The team needed to set itself apart from NASA and other private space companies.
D.
The team wanted to explore human limits for the future of space travel.
Which nuclear equation represents a spontaneous decay?.
Spontaneous fission is a nuclear equation represents a spontaneous decay.
Which nuclear equation represents a spontaneous decay?Spontaneous fission is another type of radioactive decay. In this process, the nucleus will split into two parts and free neutrons with the release of large amount of energy.
So we can conclude that spontaneous fission is a nuclear equation represents a spontaneous decay.
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A 1200 kg car moving at 2.5 m/s is struck in the rear by a 2600 kg truck moving at 6.2 m/s. If the vehicles stick together after the collision, what is their speed immediately after colliding?
Velocity: m/s
Answer: 5.0 m/s
Explanation:i had this question on my test
100 % verified!
Conservation of linear momentum
[tex]\\ \rm\Rrightarrow m1v1+m2v2=(m1+M2)v3[/tex]
[tex]\\ \rm\Rrightarrow 1200(2.5)+2600(6.2)=(1200+2600)V3[/tex]
[tex]\\ \rm\Rrightarrow 3000+16120=3800v3[/tex]
[tex]\\ \rm\Rrightarrow 19120=3800v3[/tex]
[tex]\\ \rm\Rrightarrow V3=5m/s[/tex](Approx)
Clouds are formed when water vapor in the atmosphere becomes a liquid and condenses. Condensation is a result of the difference in which of the following?
A.
air temperature and dew point temperature
B.
air pressure and air temperature
C.
dew point temperature and ocean temperature
D.
air pressure and wind speed
Answer:
B temperature and dew point temperature
When two forces act in the same direction on an object, the net force is found by ....................the forces.
1. adding
2.subtracting
3.multipling
4.dividing
Answer:
By ADDING the forces
Explanation:
write at least five electrical safety rules
a equals thirty five thats why the elephant strted to kiss the cat and the cat went upsidedown and started crying all over the ceiling
An ammeter is a device that measures _____.
the type of charge on a resistor
the current through a resistor
the voltage across a resistor
the potential of the battery
