When you step on the accelerator to increase the speed of your car, the force that accelerates the car is, the force friction of the road on the tires, the force of your foot on the accelerator, the force of the engine on the drive shaft, or the normal force of the road on the tires.(adsbygoogle = window.adsbygoogle || []).push({});

When the car begins to accelerate, new forces come into play. The rear wheels exert a force against the ground in a horizontal direction; this makes the car start to accelerate. When the car is moving slowly, almost all of the force goes into accelerating the car. This is why I think the answer is the force friction of the road on the tires because the car is exerting a force in the horizontal direction against the ground.

Sphere X, of mass 2kg is moving to the right at 10m/s. Sphere Y, of mass 4 kg, is moving to the left at 10m/s. The two spheres collide head on. The magnitude of the impulse of X on Y is: twice the magnitude of impulse of Y on X, 1/2 the magnitude of Y on X, 1/4 the magnitude of impulse, four times the magnitude of impulse of Y on X, or the same magnitude of impulse of Y on X.

I take it that it would be the same magnitude of impulse of X on Y as Y on X--> due to P(before) =P(after)

Thank you

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