Choice-'b' says the formula for kinetic energy in words.
     KE = (1/2) · (M) · (S²)
        
                    
             
        
        
        
<span> d = r*t is the basic distance equation
 d = 6000 km
 t with the tail wind = 6 hr
 r with the tail wind = speed of the plane + wind speed = s + w
 t with the head wind = 7.5 hr
 r with the head wind = speed of the plane - wind speed = s-w
 (s+w)*6 = 6000
 (s-w)*7.5 = 6000
 s + w = 1000
 s - w = 800
</span><span> 2s = 1800
 s = 900 km/h
 s + w = 1000
 w = 100
 Check the anwer by calculating the return trip.
 (900-100) * 7.5 = 800 * 7.5
 800 * 7.5 = 6000 km
 Answer: The rate of the jet in still air is 900 km/h. The rate of the wind is 100 km/hr.</span>
        
             
        
        
        
The answer is true
<span>Nuclear Fusion is 2 small nuclei to form one that's bigger</span>
        
                    
             
        
        
        
Answer:
3540.5N
Explanation:
Step one:
given data
mass m= 0.196kg
speed  v= 31m/s
distance r= 5.32cm = 0.0532m
Step two
The expression relating force, mass, velocity and distance is 
F= mv^2/r
substitute we have
F=0.196*31^2/0.0532
F=0.196*961/0.0532
F=188.356/0.0532
F=3540.5N
 
        
             
        
        
        
Answer:

Explanation:
Assume that the distance travelled initially is d.
In order to stop the block you need some external force which is friction.
If we use the law of energy conservation:

a)
Looking at the formula you can see that the mass doesn't affect the distance travelled, as lng as the initial velocity is constant (Which indicates that the force must be higher to push the block to the same speed) therefore the distance is the same.
b) If the velocity is doubled, then the distance travelled is multiplied by 4, because the distance deppends on the square of the velocity.