Question 1

Which of the following is the standard unit of time?

Accepted Answer

The standard unit of time is the second. It is denoted by the symbol 's'. While hours, minutes, and days are also used to measure time depending on the requirement, the International System of Units (SI) has accepted the second as the base unit for measuring time in scientific calculations.

Question 2

What is the basic unit of speed?

Accepted Answer

The basic unit of speed is metre per second (m/s). Since speed is calculated as distance divided by time, and the standard unit of distance is metre while that of time is second, the combination gives metre per second as the fundamental SI unit for speed.

Question 3

Which instrument is used to measure the speed of a vehicle directly?

Accepted Answer

A speedometer is an instrument used to measure the speed of a vehicle in real-time, usually displayed in km/h. An odometer, on the other hand, measures the total distance covered by the vehicle.

Question 4

An instrument that measures the distance moved by a vehicle is called:

Accepted Answer

An odometer is the device fitted in automobiles that records the total distance traveled by the vehicle. The reading is usually shown in kilometers on a small window on the dashboard.

Question 5

Which of the following represents the correct relation between speed, distance, and time?

Accepted Answer

Speed is defined as the total distance covered divided by the time taken to cover that distance. Therefore, the correct relation is Speed = Distance / Time.

Motion and Time — MP Board Class 7 Science Important Questions & Revision Notes