Physics - 1.1 Measurement and Vectors

What is a ruler used for in experiments?

To measure the length of an object by placing it so that one end is at the zero mark, not the edge of the ruler.

How should you read a ruler accurately?

Take the reading from the scale at eye level to avoid parallax error.

What determines the precision of a ruler?

The smallest division on the ruler, usually in millimetres.

How can you find the volume of an irregular solid?

Use a measuring cylinder and the water displacement method.

Describe the steps of the water displacement method.

• Partly fill the cylinder with water and record the initial volume.

• Gently lower the object into the water.

• Record the new volume.

• The difference between the two readings gives the object’s volume.

How should readings in a measuring cylinder be taken?

At eye level with the bottom of the meniscus to ensure accuracy.

What instruments are used to measure time intervals?

Stop-clocks, stopwatches, or digital timers depending on accuracy needed.

What instrument is used for short time intervals like a pendulum swing?

A stopwatch or digital timer.

What is used for long time intervals in experiments?

A wall clock or laboratory clock.

How can reaction time error be reduced when measuring time?

Start and stop timing exactly at the beginning and end of the event, and take multiple readings

How can you get an accurate value for a small distance?

Measure multiple quantities (e.g. several sheets of paper) and divide the total by the number measured.

How can you accurately measure a short time interval like a pendulum’s period?

Time several oscillations (e.g. 10 or 20) and divide the total time by the number of oscillations.

What is a scalar quantity?

A quantity that has magnitude (size) only and no direction.

What is a vector quantity?

A quantity that has both magnitude and direction.

List six scalar quantities.

Distance, speed, time, mass, energy, temperature.

List seven vector quantities.

Force, weight, velocity, acceleration, momentum, electric field strength, gravitational field strength.

How can the resultant of two vectors at right angles be found?

By calculation using Pythagoras’ theorem or graphically using a scale diagram