Question

2013

1. which object has the greatest inertia?

(1) a 0.010 - kg bullet traveling at 90. m/s
(2) a 30. kg child traveling at 10. m/s on her bike
(3) a 490 - kg elephant walking with a speed of 1.0 m/s
(4) a 1500 - kg car at rest in a parking lot

1. an 8.0 - newton wooden block slides across a horizontal wooden floor at constant velocity. what is the magnitude of the force of kinetic friction between the block and the floor?

(1) 2.4 n (2) 3.4 n (3) 8.0 n (4) 27 n

1. which situation represents a person in equilibrium?

(1) a child gaining speed while sliding down a slide
(2) a woman accelerating upward in an elevator
(3) a man standing still on a bathroom scale
(4) a teenager driving around a corner in his car
10.

Explanation:

Step1: Analyze the concept of inertia

Inertia is the property of an object to resist changes in its state of motion. The greater the mass of an object, the greater its inertia.

Step2: Compare the masses of the objects

• Object (1): mass \(m_1 = 0.010\space kg\)
• Object (2): mass \(m_2=30\space kg\)
• Object (3): mass \(m_3 = 490\space kg\)
• Object (4): mass \(m_4=1500\space kg\)

Since \(1500\space kg>490\space kg > 30\space kg>0.010\space kg\)

Answer:

(4) a \(1500 - kg\) car at rest in a parking lot