A concave lens is a lens that has at least one of its surfaces or both surfaces curved inwards. Due to this reason, this lens diverges the light that falls on it and hence is also called a diverging lens. The concave lens is thinner in the middle compared to its edges. These are used in flashlights, binoculars, telescopes, etc.
Please see attached image for reference.
 
        
        
        
Answer:
<h2>9.8 m/s²</h2>
Explanation:
<h2>Since the ball rises for 2.5 s, the time to fall is 2.5 s. The acceleration is 9.8 m/s2 everywhere, even when the velocity is zero at the top of the path. Although the velocity is zero at the top, it is changing at the rate of 9.8 m/s² downward.</h2>
 
        
             
        
        
        
The amount of matter in an object is called its, mass. How much the mass weights would be referred to as weight
        
                    
             
        
        
        
Answer:

Explanation:
From the question we are told that
Radius of vertical r= 8m
Force exerted by passengers is 1/4 of weight
Generally the net force acting on top of the roller coaster is give to be

where 


Generally the net force is given to be 



 
Mathematical we can now derive V




Therefore the speed of the roller coaster is given ton be 