Answer:
Zero
Explanation:
Net force can be defined as the vector sum of all the forces acting on a body or an object i.e the sum of all forces acting simultaneously on a body or an object.
Mathematically, net force is given by the formula;
Where;
Fnet is the net force.
Fapp is the applied force.
Fg is the force due to gravitation.
In this scenario, a stalled car is being pushed up a hill at constant velocity by three people. Thus, the net force on the car is zero because all the forces acting on any physical object is equal to zero and represents a constant velocity; by balancing or cancelling each other out.
According to Sir Isaac Newton's First Law of Motion which is known as Law of Inertia, it states that an object or a physical body in motion will continue in its state of motion at continuous velocity (the same speed and direction) or, if at rest, will remain at rest unless acted upon by an external force.
1) Size of the image: 2 cm
In order to calculate the size of the image, we can use the following proportion:

where
p = 80 m is the distance of the tree from the pinhole
q = 20 cm = 0.2 m is the distance of the image from the pinhole
= 8 m is the heigth of the object
is the height of the image
By re-arranging the proportion, we find

2) Magnification: 0.0025
The magnification of a camera is given by the ratio between the size of the image and the size of the real object:

so, in this problem we have

The best choice would be letter C hope this helps
1.5 m/s is the velocity.
9.3 m is the length of aisle, over which Distance will be covered.
Time is demanded in which the child will move the cart over the aisle with 1.5 m/s.
v=S/t
and,
t=S/v
Put values,
t=9.3/1.5=6.2 s