group of students is making model cars that will be propelled by model rocket engines. These engines provide a nearly constant thrust force. The cars are light—most of the weight comes from the rocket engine—and friction and drag are very small. As the engine fires, it uses fuel, so it is much lighter at the end of the run than at the start. A student ignites the engine in a car, and the car accelerates. As the fuel burns and the car continues to speed up, the magnitude of the acceleration will

increase.

Explanation:

According to the newton’s second law of motion force is expressed as product of mass and acceleration.

F = m a

If the force acting is constant, then.

m∝

That is if the mass of object increases the acceleration decreases and vice versa. The above equation is used when the force acting on the body is constant.

As the thrust force from the rocket engine is constant throughout there will be a variation in the mass or acceleration.

Thus, it won't stay the same.

As the weight of the car is maximum at the start because of the fuel present in the rocket engine and minimum at the end as the fuel burns throughout the journey of the car. Weight will be minimum at the end and hence acceleration is maximum at the end.

Thus, it won't decrease.

As the acceleration is going from minimum at the start to maximum at the end, therefore it is continuously increases throughout its journey.

Thus, it will increase.  

f=ma newton's second law 7x8=56n