An object swings in a horizontal circle, supported by a 1.8-m string. It swings at a speed of 3 m/s. What is the mass of the object given that the tension in the string is 90 N?

Mass = 18 kg

Explanation:

Formula for force in centripetal motion is;

F = mv²/r

We have;

Mass; m.

Speed; v = 3 m/s

radius; r = 1.8 m

Force; F = 90 N

Thus;

Making m the subject;

m = Fr/v²

m = 90 × 1.8/3²

m = 18 kg

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)