Answer:
The last one is false
Explanation:
Energy can be neither created or destroyed. It can only move from one type of energy to another.
Answer:
The total momentum of the system before the collision is 0.0325 kg-m/s due east direction.
Explanation:
Given that,
Mass of the cart, m = 250 g = 0.25 kg
Initial velocity of the cart, u = 0.31 m/s (due right)
Mass of another cart, m' = 500 g = 0.5 kg
Initial velocity of the another cart u' = -0.22 m/s (due left)
Let p is the total momentum of the system before the collision. It is given by :

So, the total momentum of the system before the collision is 0.0325 kg-m/s due east direction.
Answer:
5080.86m
Explanation:
We will divide the problem in parts 1 and 2, and write the equation of accelerated motion with those numbers, taking the upwards direction as positive. For the first part, we have:


We must consider that it's launched from the ground (
) and from rest (
), with an upwards acceleration
that lasts a time t=9.7s.
We calculate then the height achieved in part 1:

And the velocity achieved in part 1:

We do the same for part 2, but now we must consider that the initial height is the one achieved in part 1 (
) and its initial velocity is the one achieved in part 1 (
), now in free fall, which means with a downwards acceleration
. For the data we have it's faster to use the formula
, where d will be the displacement, or difference between maximum height and starting height of part 2, and the final velocity at maximum height we know must be 0m/s, so we have:

Then, to get
, we do:



And we substitute the values:

Answer:
doppler effect
Explanation:
When the relative motion of two bodies results in the wavelength becoming shorter this means that the bodies are getting closer. This is known as blue shift.
When the relative motion of two bodies results in the wavelength becoming longer this means that the bodies are getting farther. This is known as red shift.
Collectively this phenomenon is known as the Doppler effect.
Given :
The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12.
To Find :
How many grains are there in the ball?
Solution :
Volume of ball of the ballpoint is :

Now, grain size of 12 has about 520000 grains/mm³.
Therefore, number of grains are :
