Answer:
The velocity just before hitting the ground is 
Explanation:
From the question we are told that
The initial speed is 
The final speed is 
From the equations of motion we have that

Where s is the distance travelled which is the height of the cliff
So making it the subject of the the formula we have that

Where a is the acceleration due to gravity with a value 
So


Now we are told that was through horizontally with a speed of

Which implies that this would be its velocity horizontally through out the motion
Now it final velocity vertically can be mathematically evaluated as

Substituting values


The resultant final velocity is mathematically evaluated as

Substituting values


Answer:
The correct option is: B that is 1/2 K
Explanation:
Given:
Two carts of different masses, same force were applied for same duration of time.
Mass of the lighter cart = 
Mass of the heavier cart = 
We have to find the relationship between their kinetic energy:
Let the KE of cart having mass m be "K".
and KE of cart having mass m be "K1".
As it is given regarding Force and time so we have to bring in picture the concept of momentum Δp and find a relation with KE.
Numerical analysis.
⇒
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
Now,
Kinetic energies and their ratios in terms of momentum or impulse.
KE (K) of mass m.
⇒
...equation (i)
KE (K1) of mass 2m.
⇒ 
⇒
...equation (ii)
Lets divide K1 and K to find the relationship between the two carts's KE.
⇒ 
⇒ 
⇒ 
⇒ 
⇒
⇒ 
The kinetic energy of the heavy cart after the push compared to the kinetic energy of the light cart is 1/2 K.
Answer:
A The force of air resistance becomes equal in magnitude to his weight.
Explanation:
When Carlos jumped out of the helicopter, he fell with a downward force which is proportional to his weight.
His weight is the product of his mass and acceleration due to gravity.
When the parachute is deployed, air resistance between the air molecules and the surface area of the parachute generates a drag force, which acts upwards.
If the drag forces exceeds his weight, then his net force will be directed upwards.
If his weight exceeds the drag forces, then the net force on his body will be downwards.
In the case that his drag force, and his weight are equal, there will be a zero net force on him, and he will experience no acceleration.
So, if after he opens his parachute, his acceleration due to gravity decreases to zero, then we can say that this is because the force of air resistance (drag) becomes equal in magnitude to his weight.
Answer:
b. speed of a wave
Explanation:
The speed of a wave is defined as the product between the wave's frequency and the wave's wavelength:

where
is the wavelength of the wave
f is the frequency
Therefore, we see that this matches the definition listed in choice B:
b. speed of the wave.
The other options are:
a. number of waves passing a point in a second. --> frequency
c. distance between wave crests. --> wavelength
d. time for one full wave to pass. --> period
When 2 waves interefere (or collide with eachother), it usually affects the crest of the wave. If both waves collide with both crests, it will create an amplified crest, and the waves will pass through eachother afterwards. If a trough of a wave meets a crest, it will cause the crest to be lowered shortly before both continue on.