Answer:
Mass of the car is 1576 kg.
Explanation:
Let the mass of the car be
kg.
Given:
Initial velocity of the car is, 
As the car stops, final velocity of the car is, 
Change in momentum is, 
Now, we know that, momentum is given as the product of mass and velocity.
So, change in momentum is given as:

Therefore, the mass of the car is 1576 kg.
The first: alright, first: you draw the person in the elevator, then draw a red arrow, pointing downwards, beginning from his center of mass. This arrow is representing the gravitational force, Fg.
You can always calculate this right away, if you know his mass, by multiplying his weight in kg by the gravitational constant

let's do it for this case:

the unit of your fg will be in Newton [N]
so, first step solved, Fg is 637.65N
Fg is a field force by the way, and at the same time, the elevator is pushing up on him with 637.65N, so you draw another arrow pointing upwards, ending at the tip of the downwards arrow.
now let's calculate the force of the elevator

so you draw another arrow which is pointing downwards on him, because the elevator is accelating him upwards, making him heavier
the elevator force in this case is a contact force, because it only comes to existence while the two are touching, while Fg is the same everywhere
B - speed and direction are combined in another quantity, called velocity. It can be thought of as its speed in a particular direction. Speed is the corresponding scalar quantity, because it does not have a direction.
Um student a because they were there a few seconds ahead
Answer:C..net work done on the object.
Explanation: