Question

1 - Define and the concepts of frequency and period of rotation and relate them to the linear speed of an object in uniform circular motion​?

2-State the universal law of gravitation?​

Answer 1

1.

When an object moves in a circle at a constant speed its velocity (which is a vector) is constantly changing. Its velocity is changing not because the magnitude of the velocity is changing but because its direction is. This constantly changing velocity means that the object is acceleration(centripetal acceleration). For this acceleration to happen there must be a resultant force, this force is called the centripetal force .

we know that

angular speed w = v / r

v= linear speed

r = rsdius of circle

we can sy that

w = 2*pi*f or

w = 2*pi/T

where fis the frequency and T is period of rotation.

(b)

  universal law of gravitation states that any two objects exert a gravitational force of attraction on each other. The direction of the force is along the line joing the objects . The magnitude of the force is proportional to the product of the gravitational masses of the objects, and inversely proportional to the square of the distance between them.

F m1*m1

F 1/r²

so

F = G*m1*m2/r²

where G = gravitational constant.