Answer:
(a) 
(b) 
(c) 
Explanation:
(a) According to Newton's second law, the acceleration of a body is directly proportional to the force exerted on it and inversely proportional to it's mass.
(b) According to Newton's third law, the force that the sled exerts on the girl is equal in magnitude but opposite in the direction of the force that the girl exerts on the sled:
(c) Using the kinematics equation:
For the girl, we have 
and 
. So:
For the sled, we have . So:
When they meet, the final positions are the same. So, equaling (1) and (2) and solving for t:
Now, we solve (1) for 
The given data is incomplete. The complete question is as follows.
At an accident scene on a level road, investigators measure a car's skid mark to be 84 m long. It was a rainy day and the coefficient of friction was estimated to be 0.36. Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes. (why does the car's mass not matter?)
Explanation:
Let us assume that v is the final velocity and u is the initial velocity of the car. Let s be the skid marks and 
be the friction coefficient and m be the mass of car.
Hence, the given data is as follows.
v = 0, s = 84 m, = 0.36
According to Newton's law of second motion the expression for acceleration is as follows.
F = ma
= ma
= ma
a = 
Also,
= 
= 24.36 m/s
Thus, we can conclude that the speed of the car when the driver slammed on (and locked) the brakes is 24.36 m/s.
I know for a fact the answer is D. the distance traveled by the wave during one full cycle
Answer:
B'= 3.333 B
Explanation:
Lets take
Initial area = A
Magnetic field = B
The area after compression
A'=0.3 A
Magnetic field = B'
We know that flux ,Ф
Ф = B A
Given that flux is constant so
B A = B' A'
B A=B' x 0.3 A
B'= 3.333 B
It means that magnetic field will increase.
Once energy from the Sun gets to Earth, several things can happen to it:
Energy can be scattered or absorbed by aerosols in the atmosphere. Aerosols are dust, soot, sulfates and nitric oxides. When aerosols absorb energy, the atmosphere becomes warmer. When aerosols scatter energy, the atmosphere is cooled.
Short wavelengths are absorbed by ozone in the stratosphere.
Clouds may act to either reflect energy out to space or absorb energy, trapping it in the atmosphere.
The land and water at Earth's surface may act to either reflect energy or absorb it. Light colored surfaces are more likely to reflect sunlight, while dark surfaces typically absorb the energy, warming the planet.
Albedo is the percentage of the Sun's energy that is reflected back by a surface. Light colored surfaces like ice have a high albedo, while dark colored surfaces tend to have a lower albedo. The buildings and pavement in cities have such a low albedo that cities have been called "heat islands" because they absorb so much energy that they warm up.
