Question

the forces acting on an object are balanced.
what could the object be doing?
choose 2 answers:
a moving at a constant speed while turning
b not moving
c moving in a straight line while changing speed
d moving in a straight line at a constant speed

Explanation:

To solve this, we use Newton's first law (law of inertia): balanced forces mean no net force, so an object either remains at rest (not moving) or moves with constant velocity (constant speed in a straight line, since velocity includes direction).

• Option A: Turning means changing direction, so velocity changes (unbalanced forces needed for acceleration, including centripetal acceleration for turning). Eliminate A.
• Option B: Not moving (at rest) is consistent with balanced forces (net force = 0, so no change in motion from rest).
• Option C: Changing speed means acceleration (unbalanced forces needed for acceleration). Eliminate C.
• Option D: Moving in a straight line at constant speed means constant velocity, which is consistent with balanced forces (no net force, so motion remains unchanged).

Answer:

B. not moving, D. moving in a straight line at a constant speed