Answer:
v = √ 2 G M/ 
Explanation:
To find the escape velocity we can use the concept of mechanical energy, where the initial point is the surface of the earth and the end point is at the maximum distance from the projectile to the Earth.
Initial
Em₀ = K + U₀
Final
= 
The kinetic energy is k = ½ m v²
The gravitational potential energy is U = - G m M / r
r is the distance measured from the center of the Earth
How energy is conserved
Em₀ =
½ mv² - GmM / = -GmM / r
v² = 2 G M (1 / – 1 / r)
v = √ 2GM (1 / – 1 / r)
The escape velocity is that necessary to take the rocket to an infinite distance (r = ∞), whereby 1 /∞ = 0
v = √ 2GM /
(a) 10 GHz is the frequency of microwave radiation.
(b) 0.167 ms is required by the microwave to travel between two mountains.
Answer:
Explanation:
(a). 1 MHz is the frequency of microwave radiation.
(b) 0.167 ms is required by the microwave to travel between two mountains.
Answer:
Explanation:
a. Frequency is the measure of number of times a same thing will be repeated in a given time interval for a given time. And wavelength is the measure of distance between two successive crests or troughs. So wavelength and frequency are inversely proportional to each other. And velocity of light is the proportionality constant.
So frequency of microwave radiation = Speed of light/Wavelength of radiation
Frequency = 
Frequency = 
So 10 GHz is the frequency of microwave radiation.
b). As microwave is a part of light waves, so it will be experiencing the speed of light.
As the speed is 3*
m/s and the distance between the two mountains is given as 50 km, then time can be calculated as
Time = Distance/Velocity
Time = 
So time = 0.167 ms.
Thus, 0.167 ms is required by the microwave to travel between two mountains.
Answer:False
Explanation:
Work is being done on a body when it causes displacement of body on the application of force
When we pull the door by a force it causes zero displacements of the door. So we can say that work done on it is zero.
Thus the above-given statement is false
Answer:
Explanation:
During the first .8 s , the elevator is under acceleration . It starts from initial velocity u = 0 , final velocity v = 1.2 m /s , time = .8 s
v = u + at
1.2 = 0 + .8 a
a = 1.2 / .8
= 1.5 m /s²
During the acceleration in upward direction , let reaction force of ground on man be R .
Net force on man = R - mg
Applying Newton's 2 nd law
R - mg = ma
R = m ( g + a )
= 72 ( 9.8 + 1.5 )
= 813.6 N .
This reaction force will be measured by spring scale , so reading of spring scale will be 813.6 N .
