Answer:
1185 N
Explanation:
From Newton’s second law of motion,  
F=ma where m= mass of motorcycle, a is acceleration of the motorcycle and F=Force
Net force acting on motorcycle  is given by
 is given by   
Where F is force acting on motorcycle and f is frictional force
Substituting F-f for  
 hence  ma= F- f Substituting a with 3, m with 245Kg and f with 450N as provided
 hence  ma= F- f Substituting a with 3, m with 245Kg and f with 450N as provided
245*3= F- 450
F=245*3 +450= 1185 N
 
        
             
        
        
        
Answer:
A. Mass(only) 
Explanation:
The correct answer is A because if the balloon is filled with air, it's filled with matter. Matter is anything that has space and occupies mass. The air occupies mass in the balloon but that doesn't mean that the balloon is heavier. People confuse themselves with mass and weight saying it means the same thing. Mass, like I said is the amount of matter an object contains whereas weight is how much an object weighs. 
 
        
                    
             
        
        
        
Answer:
a) m = 69.0 kg
b) release some gas in the opposite direction to the astronaut's movement 
Explanation:
a) Let's use Newton's second law
          F = m a
          m = F / a
          m = 60.0 / 0.870
          m = 69.0 kg
b) when we exert a force on the astronaut it acquires a momentum po, as the astronaut system plus spacecraft is isolated, the momentum is conserved
          p₀ = p_f
          m v = M v '
          v ’=  
so we see that the ship is moving backwards, but since the mass of the ship is much greater than the mass of the astronaut, the speed of the ship is very small.
One method to avoid this effect is to release some gas in the opposite direction to the astronaut's movement so that the initial momentum of the astronaut plus the gas is zero and therefore no movement is created in the spacecraft.
 
        
             
        
        
        
All except C, feelings are not physical.
        
                    
             
        
        
        
Answer: 490N
Explanation:
Newton is the unit for force. Force = mass x acceleration
F=N m=50kg a=9.8 (earth's acceleration of gravity)
F=50X9.8
F≈490N