5 points A car, of mass 1600 kg, is travelling at a speed of 20 m/s when the driver
applies the brakes. The car decelerates at a constant rate and stops. The
braking force used to stop the car and driver was 8000 N. Calculate the
braking distance of the car in m. This is a two step problem, you must
calculate a value and use it to find the final answer.

The braking distance of the car is 40 m

Explanation:

The two steps are;

1) Calculation (finding) of the initial kinetic energy , K.E., of the car

2) Calculation (finding) of the braking distance from the calculated K.E., of the car

The initial Kinetic energy of the car, K.E. = 1/2×m×v²

Where;

m = The mass of the car = 1,600 kg

v = The velocity of the car = 20 m/s

∴ K.E. = 1/2 × 1,600 kg × (20 m/s)² = 320,000 joules

2) The work done in stopping the car, W = The braking force, 'F' × The braking distance, 'd'

∴ W = F × d

Where;

F = The braking force = 8,000 N

d = The braking distance of the car

By energy conservation principle, the work, 'W', that is required to stop the car = The initial kinetic energy of the car, K.E.

∴ W = K.E. = 320,000 joules

Therefore, by substituting the known values for the variables, we have;

320,000 J = 8,000 N × d

∴ d = 320,000 J/(8,000 N) = 40 m

The braking distance of the car, 'd' = 40 m.

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the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.