Question

a train travels north at 103 km/h. this is an example of
a. velocity
b. speed
c. acceleration
d. speed and acceleration
what is the speed of a rocket that travels 9,000 meters in 12 seconds?
a. 0.001 seconds
b. 750 seconds
c. 750 m/s
d. 108,000 m/s
if john mows 11.5 meters of lawn from east to west in 7.1 seconds, what is the velocity of the lawnmower?
a. 0.6 m/s east
b. 0.6 m/s west
c. 1.6 m/s east
d. 1.6 m/s west
in 17.2 seconds, a shopping cart is pushed 15.6 meters towards the west. what is the velocity of the cart?
a. 1.6 m/s east
b. 0.9 m/s west
c. 1.1 m/s west
d. 1.6 m/s west

Explanation:

Q1

Velocity is speed with direction. Here, the train travels North (direction) at 103 km/h (magnitude). Speed is just magnitude. Acceleration is rate of change of velocity. Since it has magnitude and direction, it's velocity.

Step1: Use speed formula

Speed \(v=\frac{d}{t}\), where \(d = 9000\) m and \(t=12\) s.

Step2: Calculate speed

\(v=\frac{9000}{12}=750\) m/s. Options A and B are time units (not speed). Option D is incorrect calculation.

Step1: Use velocity formula

Velocity \(v=\frac{d}{t}\), \(d = 11.5\) m (West), \(t = 7.1\) s.

Step2: Calculate magnitude

\(v=\frac{11.5}{7.1}\approx1.6\) m/s. Direction is West (as motion is West).

Answer:

A. Velocity

Q2