1. Convert the following: a. 15.0 kg to N
b. 85.0 N to kg
c. 220 lb to N
d. 550 N to lb.
2. What force is needed to accelerate the stone of
mass 25.0 kg upward at 5.00 m/s2?
Draw a free body diagram.

3. A rocket that weighs 7850 N on the earth is fired.
The force of propulsion is 1.04 x 104 N.
a. Find the mass of the rocket.
b. The acceleration of the rocket
c. The velocity of the rocket at the end of 10.0 s.
d. The displacement at the end of the above time
frame ( 10.0 s)
4. A force of 15.0 N is necessary to keep the 4.0 kg
wooden block moving along a table top at a uniform
velocity . Calculate the co-efficient of friction.
5. A car moving on a high way has a mass of 400 kg.
The coefficient of friction between the tire and the
car is 0.2. What acceleration will a force of 2500 N
produce on the car?

Ineed the answers for these promblems i have

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.

What does the law of conservation of mass state?