Answer:
40N
Explanation:
Since both weights are connected to one string, you can say that the tensions above each are equal to each other.
If you do the sum of forces for the 4kg mass, then the tension comes out to 40N (if we take gravity to be 10m/s²). But that seemed too good to be true, so I decided to do the work for the 7kg mass as well [which included finding the normal force (N) and plugging it into the sum of forces for the 7kg mass] to find that it also gives 40N as the answer.
If I were to put my process into steps:
- Write out the sum of Forces for both masses
- Set them equal to each other to find normal force (because this is the only unknown)
- Calculate and compare the two tensions to see if they are equal
*This all seems to line up perfectly, but do let me know if my answer doesn't match up with what you might find to he the answer later on.
Answer:
Mass and velocity.
Explanation:
Kinetic energy <u>is the energy that an object has due to its movement</u>, mathematically it is represented as follows:

where
is the mass of the object, and
is its velocity at a given point in time.
So we can see that to find the kinetic energy just before the ball hits the gound, we need the quantities:
- mass of the ball
- velocity of the ball before it hits the ground
With the knowledge of these two quantities the kinetic energy of the ball before touching the gound can be determined.
Answer:
We know from the basic speed distance relation that

Since the car started from rest and it covered the distance between the 2 officer's in 19 minutes we have speed of the car

Which clearly exceeds the limit of 
Answer:
5 seconds
Explanation:
<em>Acceleration = (final velocity - initial velocity) ÷ time</em>
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I got inner ear for my answer if wrong sorry