Question

1. two objects have the same size and shape, but the first is 3 times as heavy as the second. when they are dropped simultaneously from a cliff, they reach the ground at the same time (neglecting air resistance), but the second object has less _ (1 point)

Explanation:

Step1: Recall the concept of free - fall

In free - fall (neglecting air resistance), all objects near the Earth's surface have the same acceleration \(g\approx9.8\ m/s^{2}\), and the time \(t\) it takes for an object to fall from a height \(h\) is given by \(h = v_0t+\frac{1}{2}gt^{2}\). Since they are dropped (\(v_0 = 0\)), \(h=\frac{1}{2}gt^{2}\), and the time of fall only depends on the height and the acceleration due to gravity.

Step2: Recall the concept of momentum

Momentum \(p=mv\). When they reach the ground, they have the same velocity \(v\) (because \(v = gt\) and \(t\) is the same for both as they are dropped from the same height and have the same acceleration \(g\)). But the first object has a mass \(m_1\) and the second has a mass \(m_2\) such that \(m_1 = 3m_2\).

Step3: Compare the momentums

The momentum of the first object \(p_1=m_1v\) and the momentum of the second object \(p_2=m_2v\). Since \(m_1 = 3m_2\), \(p_1>p_2\).

Answer:

Momentum