A box attached to a spring is being pulled across a flat frictionless surface. The spring constant is 45 N/m, the box is accelerating at 1.3 m/s2, and the spring is stretched by 0.88 m. What is the mass of the box?
26 kg
O 38 kg
30 kg
O 33 kg
Pl help

Mass = 30.46 kg

Explanation:

Given the following data;

Spring constant = 45 N/m

Acceleration = 1.3 m/s²

Extension = 0.88 m

To find the mass of the box;

First of all, we would determine the force acting on the spring.

Force = spring constant * extension

Force = 45 * 0.88

Force = 39.6 N

Next, we find the mass using Newton's second equation of motion.

Force = mass * acceleration

39.6 = mass * 1.3

Mass = 39.6/1.3

Mass = 30.46 kg

see earlier

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.