A bird flies at a speed of 15 m/s for 10s, 20 m/s for 20s, and 30 m/s for 15s. what is the birds average speed

Average speed = (total distance) / (total time)

First segment:

15 m/s for 10 sec;  distance covered = (15 x 10) = 150 m

Second segment:

20 m/s for 20 sec; distance covered = (20 x 20) = 400 m

Third segment:

30 m/s for 15 sec; distrance covered = (30 x 15) = 450 m

Total time = (10s + 20s + 15s) = 45 sec

Total distance = (150m + 400m + 450m) = 1,000 m (1 km)

Average speed = (1,000 m) / (45 sec) = 22.22 m/s

40 newtons

Explanation:

It will be equal to the amount of force pushing down because otherwise he'd just fall through the floor.

Heres newtons law for the principle

Newton's third law is: For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object.