The presence of mass makes gravity. Doesn't matter whether it's a planet, a black hole, a puppy, or a speck of dust.
Answer:
A car
Explanation:
A car can travel 100 m in 5 seconds
Hope this helps!
Answer:
A simple pulley is a wheel with a rope that allows you to pull one end and have it lift whatever is on the other end. A modern, common example of this is a crane, often used in construction.
Explanation:
The meter is the S.I.unit for length.
Answer: 430 nm.
Explanation:
The relation of wavelength and frequency is:
Formula used :
where,
= frequency =
= wavelength = ?
c = speed of light = 
Now put all the given values in this formula, we get

Thus the wavelength (in nm) of the blue light emitted by a mercury lamp is 430 nm.