Work formula:

F = 50N, d = 1.0 m
When you lift something straight up, the angle of the force is 90º
cos(90º) is 0, so there's no work done when you lift the microwave off the ground

F = 50N, d = 1.0 m
When you push the microwave, the angle is 0º and cos(0º) is 1. So there is work done here:


total work = 50 joules
Answer:
The observer detects light of wavelength is 115 nm.
(b) is correct option
Explanation:
Given that,
Wavelength of source = 500 nm
Velocity = 0.90 c
We need to calculate the wavelength of observer
Using Doppler effect

Where, 


Hence, The observer detects light of wavelength is 115 nm.
Answer:
The amount of caffeine left after one half life of 5 hours is 15 oz.
Explanation:
Half life is the time taken for a radioactive substance to degenerate or decay to half of its original size.
The half life of caffeine is 5 hours. So ingesting a 30 oz, this would be reduced to half of its size after the first 5 hours.
So that:
After one half life of 5 hours, the value of caffeine that would be left is;
= 15 oz
The amount of caffeine left after one half life of 5 hours is 15 oz.
Answer:
f = 878,080 N
Explanation:
mass of pile driver (m) = 2100 kg
distance of pile driver to steel beam (s) = 5 m
depth of steel driven (d) = 12 cm = 0.12 m
acceleration due to gravity (g0 = 9.8 m/s^{2}
calculate the average force exerted on the pile driver by the beam.
- from work done = force x distance
- work done = change in potential energy of the pile driver
- equating the two equations above we have
force x distance = m x g x (s - d)
f x 0.12 = 2100 x 9.8 x (5- (-0.12))
d = - 0.12 because the steel beam went down at we are taking its
initial position to be an origin point which is 0
f = ( 2100 x 9.8 x (5- (-0.12)) ) ÷ 0.12
f = 878,080 N
Answer:
<u>B</u>
Explanation:
Planets have different year lengths because it depends how far they revolve from a celestial body. Each planet has its own orbital period. Planets closer to the star will have a lower orbital period compared to the ones that lie far away from it.