Suppose quantity s is a length and quantity t is a time. suppose the quantities vand aare defined by v = ds/dt and a = dv/dt. (a) what is the dimension of v? (b) what is the dimension of the quantity a?
what are the dimensions of (c)vdt, (d) a dt, and (e) da/dt?

Explanation:

(a) Velocity is given by :

s is the length of the distance

t is the time

The dimension of v will be,      

(b) The acceleration is given by :

v is the velocity

t is the time

The dimension of a will be,

(c) Since,

(d) Since,

(e)

Hence, this is the required solution.

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.

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.