Answer:
Doppler shift of the starlight
Explanation:
To predict the movement of a star, we compare the spectra of elements found in star (H, He Na etc.), first spectra which are obtained from star and second spectra from laboratory. If spectral lines of the spectra obtained from star, are shifting towards red end (called red shift) then star is going away from earth and if shifting is towards blue (called blue shift), then star is approaching the earth. This is Doppler's shift.
Answer:
Momentum, 
Explanation:
Given that,
Mass of a mosquito, m = 0.000015 kg
Velocity of the mosquito, v = 5.2 m/s
We need to find the momentum of the mosquito. The momentum of an object is given by :
p = mv
Put all the values in the above formula.
So, the momentum of the mosquito is 
.
1250 J in 5 sec= 250 Joule(s) per second (1250/5 0
250 Joules per second = 250 Watts ( 1J/s = 1 Watt per definition)
250 Watts output = 250/0.65 efficiency = 384 Watts input
1 Horsepower = 732 Watts
Motors 1 Horsepower and under are made in certain step sizes like
3/4 , 1/2 , 1/3, 1/4, 1/16 1/20 of a Horsepower.
3/4 Horsepower is 549 Watts
1/2 Horsepower is 366 Watts
so you need to 3/4 horsepower motor to achieve 1250 J of work in 5 seconds.
The answer I believe is c
Explanation
During the day when temperatures are higher, the snow melts and water enters the cracks in the rock. When the temperature drops below 0°C the water in the crack freezes and expands by about 9 per cent. This makes the crack larger.
Answer:
Explanation:
The bike's acceleration can be found by using the following suvat equation:
where
v is the final velocity of the bike
u is the initial velocity
a is the acceleration
s is the distance covered
For the bike in the problem,
u = 0
v = 7 m/s
d = 40 m
Solving the equation for a, we find the acceleration:
