Answer:
<em>The athlete will rise 1.10 meters off the ground</em>
Explanation:
<u>Vertical Motion</u>
If an object is launched vertically upwards at an initial speed vo, then it will reach a maximum height given by
The athlete can exert a net force upwards equal to twice his weight. It makes him accelerate upwards at
The speed at the end of his push can be computed by
Replacing the value of a obtained above:
where y is the length of this crouch
This is the initial speed of this vertical launch, thus
Answer:
The net force = 0
Explanation:
The given information includes;
The mass of the crate = 250 kg
The way the helicopter lifts the crate = Uniformly (constant rate (speed), no acceleration)
In order to pull the crate upwards, the helicopter has to provide a force equivalent to the weight of the crate keeping the helicopter on the ground.
The weight of the crate = The mass of the crate × The acceleration due gravity acting on the crate
The weight of the crate, 
↓ = 250 kg × 9.81 m/s² = 2,452.5 N
The force the helicopter should provide to just lift the crate, 
↑ = The weight of the crate = 2,452.5 N
The net force, 
= ↑ - ↓ = 2,452.5 N - 2,452.5 N = 0
The net force = 0.
Answer:
remains the same, but the apparent brightness is decreased by a factor of four.
Explanation:
A star is a giant astronomical or celestial object that is comprised of a luminous sphere of plasma, binded together by its own gravitational force.
It is typically made up of two (2) main hot gas, Hydrogen (H) and Helium (He).
The luminosity of a star refers to the total amount of light radiated by the star per second and it is measured in watts (w).
The apparent brightness of a star is a measure of the rate at which radiated energy from a star reaches an observer on Earth per square meter per second.
The apparent brightness of a star is measured in watts per square meter.
If the distance between us (humans) and a star is doubled, with everything else remaining the same, the luminosity remains the same, but the apparent brightness is decreased by a factor of four (4).
Some of the examples of stars are;
- Canopus.
- Sun (closest to the Earth)
- Betelgeuse.
- Antares.
- Vega.
Answer with Explanation:
a.Intensity of radiation is directly proportional to the frequency of radiation
When the intensity of radiation increases then the frequency of radiation increases and therefore, the number of photo-electrons emitted by the metal increases.
b.When all of the wavelength in the radiation are increased by the same amount
We know that
Frequency is inversely proportional to the wavelength.
Therefore, the frequency decrease .
When the frequency decreases then the number of photo-electrons emitted by the metal decrease.
c.When the work function of the metal is increased then the gain of kinetic energy decreases .
When energy decreases then the number of photo-electrons emitted by the metal decreases.
Answer:
The efficiency of each cycle of a heat engine is 30 %.
Explanation:
Given that,
Heat absorbed by a heat engine, Q = 64 kcal
Heat exhaust by a heat engine, Q' = 42 kcal
We need to find the efficiency of each cycle. The efficiency of heat engine is defined as the ratio of work output to the energy supplied. It is given by :
or
So, the efficiency of each cycle of a heat engine is 30 %. Hence, this is the required solution.
