Question: How fast was the arrow moving before it joined the block?
Answer:
The arrow was moving at 15.9 m/s.
Explanation:
The law of conservation of energy says that the kinetic energy of the arrow must be converted into the potential energy of the block and arrow after it they join:

where
is the mass of the arrow,
is the mass of the block,
of the change in height of the block after the collision, and
is the velocity of the arrow before it hit the block.
Solving for the velocity
, we get:

and we put in the numerical values
,



and simplify to get:

The arrow was moving at 15.9 m/s
I think the correct answer is C
Answer:
610 meters.
Explanation:
Because Jim released the accelerator, the truck started to slow down, so the friction force will eventually stop the truck.
the kinetic energy of the truck just after Jim released the pedal is:

The work done by the friction force is given by:

Gravitational potential energy can be given by the equation
PE = mgh
where m is the mass,
g is the gravitational constant 9.81 or 10 depending on rounding
and h is the height
well weight is a force equiavlent to
W= m*g
so comparing that to the potential energy equation, divide the potential energy by the height and you will get weight in Newtons
-reflection and refraction of light
-dispersion of light
-absorption of light
-polarization of light