Final answer:
When a seismograph's weight is attached to a rod instead of a spring, the weight would not be able to oscillate and hence the seismograph would fail to function properly.
Step-by-step explanation:
If the weight of a seismograph were attached to a rod instead of a spring, the weight would not oscillate. Oscillation occurs in a seismograph due to the elastic nature of the spring, which allows the weight to move back and forth.
If the weight were attached to a rod, there would be no restoring force to bring the weight back to its equilibrium position, resulting in no oscillation.
If a seismograph's heavy weight were attached to a rod instead of a spring, the weight would not oscillate. The spring is responsible for the oscillatory motion of the weight in response to earth tremors. The elasticity of the spring and the force it can exert when it's displaced from its equilibrium position enables it to move.
A rod, being rigid, would not provide the necessary elasticity for oscillatory motion, and thus, the seismograph would not function effectively in recording earth tremors.