A train moving at 72 km/h applies brakes and comes to a stop in 5 seconds. What is the acceleration of the train?
Practice Questions
1 question
Q1
A train moving at 72 km/h applies brakes and comes to a stop in 5 seconds. What is the acceleration of the train?
-4 m/s²
-5 m/s²
-6 m/s²
-7 m/s²
First convert speed to m/s: 72 km/h = 20 m/s. Using the formula: acceleration = (final velocity - initial velocity) / time = (0 - 20) / 5 = -4 m/s².
Questions & Step-by-step Solutions
1 item
Q
Q: A train moving at 72 km/h applies brakes and comes to a stop in 5 seconds. What is the acceleration of the train?
Solution: First convert speed to m/s: 72 km/h = 20 m/s. Using the formula: acceleration = (final velocity - initial velocity) / time = (0 - 20) / 5 = -4 m/s².
Steps: 5
Step 1: Convert the speed from kilometers per hour (km/h) to meters per second (m/s). To do this, use the conversion factor: 1 km/h = 1/3.6 m/s. So, 72 km/h = 72 / 3.6 = 20 m/s.
Step 2: Identify the initial velocity (the speed of the train before braking) and the final velocity (the speed of the train after it stops). The initial velocity is 20 m/s and the final velocity is 0 m/s.
Step 3: Use the formula for acceleration: acceleration = (final velocity - initial velocity) / time. Here, final velocity is 0 m/s, initial velocity is 20 m/s, and time is 5 seconds.
Step 4: Plug the values into the formula: acceleration = (0 - 20) / 5.
