Question

1. What is the mass of an object whose weight is 49 N?
2.State three Kepler's law of planetary motion.
[5 MARKS]

Answer 1

Problem: 2 Marks
Laws: 3 Marks

1. Here, Weight, W = 49 N

Mass, m = ? (To be calculated)

And, Accelertion due to gravity, $g=9.8m/s^2$

Now, putting these valuesin the formula,

$W=m\times g$

we get: $49=m\times 9.8$

$m=\frac{49}{9.8}$

$m=5kg$

Thus, the mass of the object is 5 kilograms.

2.
First law: All planets revolve round the sun in eliptical orbits with sun at one of the foci.
Second law: A line joining any planet to the sun sweeps out equal areas in equal intervals of time.
Third law: The square of the period of any planet around the sun is proportional to the cube of the planet's mean distance from the sun.