Answer:
Because the gravitational attraction of the Sun hold them in motion around it
Explanation:
For an object travelling in a straight path at constant velocity, the net force acting on the object must be zero.
The planets in the Solar System, however, do not experience a zero net force: in fact, the Sun exerts a gravitational attraction on them, whose magnitude is given by

where
G is the gravitational constant
M is the mass of the Sun
m is the mass of the planet
r is the average distance between the Sun and the planet
Due to the presence of this force, the Sun makes the planets 'deviating' from their straight path, forcing them to following an elliptical path around the Sun.
Answer:
Speed, v = 5 m/s
Explanation:
We have,
The length of the football field, l = 100 m
A person takes 20 seconds to run its length.
It is required to find the speed of the person with which he should run. The distance covered divided by time taken is called its velocity.

So, the speed of the person is 5 m/s.
Answer:
Time = 12.27seconds
Explanation:
Given
Speed = 25miles/hour
Distance = 150 yards = 150(0.000568182)miles
Distance (in miles) = 0.0852273miles
Get the time
Speed = Distance/Time
Time = Distance/Speed
Time = 0.0852273/25
Time = 0.0034hours
Time = 0.0034 * 3600secs
Time = 12.27seconds