Answer:
B. 17m/s
Explanation:
This question contains a graph that illustrates the relationship between the speed of a car over time. The graph shows that one can make an inference of the amount of time it takes for the car to cover a particular speed and vice versa. 
In this case, after 3 seconds, the speed of the car will be 17 m/s. This inference was got by tracing the position of 3s in the x-axis to the value on the y-axis. Doing this, the best inference for the speed of the car after 3 seconds is 17m/s.
 
        
             
        
        
        
Answer:
15193.62 m/s
Explanation:
t = Time taken = 6.5 hours
u = Initial velocity = 0 (Assumed)
m = Mass of rocket = 1380 kg
F = Thrust force = 896 N
v = Final velocity
a = Acceleration of the rocket
Force

Equation of motion

The velocity of the rocket after 6.5 hours of thrust is 15193.62 m/s
 
        
             
        
        
        
The conservation of energy always holds true even when not clearly observable in machines that are less than 100% efficient. More often than not a machine will suffer energy losses (e.g. consider for a cooling fan: friction between the rotating blades, drag resistance in the air the fan is pushing around, resistance in the wire, and heat radiating/conducting away from the circuitry).
 
        
                    
             
        
        
        
Its the floor pushing up on the player, this one is correct 
 
        
                    
             
        
        
        
Answer:
Equal to the weight of the object
Explanation:
There are two forces acting on the object hanging on the string:
- The tension in the string, T, acting upward
- The weight of the object, mg, acting downward
We can write Newton's second law as:

where a is the acceleration of the object.
Here we are told that the elevator is moving at constant speed: this means that the acceleration of the object is zero, therefore a = 0 and the equation becomes

therefore, the tension in the string is equal to the weight of the object.