Velocity And Acceleration Quiz

Explanation
The average speed for the entire trip can be calculated by dividing the total distance traveled by the total time taken. In this case, the total distance traveled is 50 km + 10 km = 60 km, and the total time taken is 4 hours. Dividing 60 km by 4 hours gives us an average speed of 15 km/hr.

Explanation
The cars have different total displacements (40 meters for Car 1 and 64 meters for Car 2).
However, they have the same average velocity because the average velocity is determined by the ratio of displacement to time. Both cars have an average velocity of 8 meters per second.
So, during their periods of travel, the cars definitely had the same average velocity. The other options (total displacement, average speed, change in momentum) are not the same for the two cars based on the given information.

Explanation
The magnitude of acceleration can be calculated using the formula: acceleration = (final velocity - initial velocity) / time. In this case, the initial velocity is 30 m/s, the final velocity is 10 m/s, and the time is 4.0 seconds. Plugging these values into the formula, we get: acceleration = (10 m/s - 30 m/s) / 4.0 s = -20 m/s / 4.0 s = -5.0 m/s2. Since acceleration is a vector quantity, the magnitude is the absolute value, so the magnitude of the car's acceleration is 5.0 m/s2.

Explanation
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Explanation
The time it takes for the two cars to collide can be found by dividing the distance between them by the sum of their speeds. In this case, the distance between the cars is 400 meters and the sum of their speeds is 30 + 20 = 50 meters per second. Dividing 400 by 50 gives us 8 seconds, which is the correct answer.