In each case, lifting or pushing, why must you exert a force to move the object? q1-2: how much more effort is required to lift or push two bricks or masses instead of just one?

Newton's first law applies. An object at rest will stay that way until a force is applied.Any amount of effort can be applied to any amount of mass (in the ideal case). The question is not sufficiently specific.

Explanation:

A force is required to move an object because the object will stay at rest until a force is applied.

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The effort required to lift or push two masses instead of one depends on the desired effect. For the same kinetic energy, no more effort is required. For the same momentum, half the effort is required for two masses. For the same velocity, double the effort is required.

B

Explanation: