Question

A city bus accelerates away from a bus stop at the acceleration shown. At the next stop, a tourist boards the bus with 1,000-kg of recording equipment, and when the bus driver starts going again, he notices he has to press harder on the gas pedal to maintain the same acceleration.



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Which TWO observations provide the BEST evidence to support the claim that the force needed to accelerate an object is directly proportional to its mass?



A.
The force of the engine decreased after the tourist boarded the bus.

B.
The acceleration of the bus increased after the tourist boarded the bus.

C.
The acceleration of the bus decreased after the tourist boarded the bus.

D.
The acceleration of the bus is in the same direction of the force of the engine.

E.
The force of the engine increased when the bus driver pressed harder on the gas pedal.

Answer 1

C and E.

C: After the tourist (extra mass) boarded, the bus's acceleration decreased for the same engine setting — consistent with a = F/m.
E: The engine force increased when the driver pressed harder to maintain acceleration — showing larger mass requires larger force to get the same acceleration.