Whats the formula to find the area of a circle?

3 answers

areacircle=PI*radius^2
Could you please check my work and help me with a couple.

An airplane that flies at 100 km/h with a 10 km/h tailwind travels at 110 km/h relative to the ground. If it instead flies into a 10 km/h headwind, its groundspeed is :

110 km/h /2= 55 km/h



The average speed of a horse that gallops a distance of 10 kilometers in a time of 30 minutes is

(10 km)(30 min)= 300 km


What is the acceleration of a car that maintains a constant velocity of 100 km/hr for 10 seconds?

100 km/hr /10 s= 10 km/h s


Ten seconds after starting from rest, an object falling freely downward will have a speed of about (This question I don't understand)

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? (This one I don't understand)



If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about

would it be 10 m/s?



A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. How far below the level from which it was thrown is the rock 2 seconds later?

(4.9 m/s)(2 s)=9.8 m
Could you please check my work and help me with a couple.

An airplane that flies at 100 km/h with a 10 km/h tailwind travels at 110 km/h relative to the ground. If it instead flies into a 10 km/h headwind, its groundspeed is :

110 km/h /2= 55 km/h

The average speed of a horse that gallops a distance of 10 kilometers in a time of 30 minutes is

(10 km)(30 min)= 300 km

What is the acceleration of a car that maintains a constant velocity of 100 km/hr for 10 seconds?

100 km/hr /10 s= 10 km/h s

Ten seconds after starting from rest, an object falling freely downward will have a speed of about (This question I don't understand)

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? (This one I don't understand)

If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about

would it be 10 m/s?

A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. How far below the level from which it was thrown is the rock 2 seconds later?

(4.9 m/s)(2 s)=9.8 m