Are These Force-Related Statements True or False?

[ttk3]

The following statements are true/false... I'll give my answer and explanation. Please point out where I'm wrong.

If two objects have the same acceleration, they are under the influence of equal forces.
false
a change in mass can effect the force.

If a net force acts on an object, the object's speed will change.
True
A net force causes a change in velocity


During the collision of a car with a large truck, the car exerts a lesser force on the truck than the truck exerts on the car.
false
Newton's third law states each reaction has an equal and opposite reaction


If an object's speed does not change, no net force is acting on the object.
True
A net force is need to change velocity


During the collision of a car with a large truck, the truck exerts an equal size force on the car as the car exerts on the truck.
True
Again, Newton's third law

 

[Doc Al]

If two objects have the same acceleration, they are under the influence of equal forces.
false
a change in mass can effect the force.

Good.

If a net force acts on an object, the object's speed will change.
True
A net force causes a change in velocity

Careful: Velocity can change in either magnitude (speed) or direction. Consider circular motion.

During the collision of a car with a large truck, the car exerts a lesser force on the truck than the truck exerts on the car.
false
Newton's third law states each reaction has an equal and opposite reaction

Good.

If an object's speed does not change, no net force is acting on the object.
True
A net force is need to change velocity

Careful: see above.

During the collision of a car with a large truck, the truck exerts an equal size force on the car as the car exerts on the truck.
True
Again, Newton's third law

Good.