PHYSICS

MOTION

ACTIVITIES

Introduction

Basic concepts

Ticker-timer experiment

Learners' activities

 

MOTION: VELOCITY AND ACCELERATION

TICKER-TIMER EXPERIMENT

TASK 1

AIM:

This activity is about velocity, acceleration, and deceleration,as influenced by forces of friction and gravitation.

And you will be introduced to a device called a ticker-timer.

At the end of the activity, the learner should be able to:

  • Describe how friction compensation happens on a runway.

  • Describe how a ticker-timer works.

  • Describe the experimental procedures to measure the velocity of a trolley.

  • Identify ticker-timer tapes that show uniform velocity and those that show accelerated motion.

  • Calculate velocity from a ticker tape.

  • Determine acceleration due to gravity using a ticker-timer.

APPARATUS:

To set up this activity, the following equipment is needed: Trolleys, runways, ticker-timers, ticker tapes, and rulers.

PROCEDURES:

  • Set up the trolley to move on a horizontal runaway as shown in figure below (under the guidance of your teacher). A ticker tape passing through the ticker timer is attached to the trolley.

  • Observe and describe how the trolley moves along the runaway.

  • Suggest how the trolley can be made to moves down the runway at a constant speed.

  • Ask your teacher to help you produce various tapes for constant velocity and accelerated motion.


  • Examine the various tapes obtained

  • Describe the various tapes that show uniform velocity and those showing accelerated motion.

 

Tape (take initial part of the tape to be on the left)

Describe in each case how spacing between dots varies

Describe the type of motion represented

A

 

 

B

 

 

C

 

 

D

 

 

E

 

 

TASK 2

DETERMINING VELOCITY FROM THE TICKER TAPE

Answer the following questions:

  • If the frequency of the ticker timer is f, what is the time interval between two successive dots?.

  • If frequency of the ticker timer is 50Hz, what is the time interval for the following cases:

    • From the 1st to the 2nd dot;

    • From the 1st to the 5th dot;

    • From the 1st to the 100th dot;

The following examples show various tapes each of length 8cm obtained using a ticker timer of frequency 50Hz.
In each case find the time interval of the tape and the velocity in ms-1.

 

Tape

Time interval

Velocity

A

 

 

B

 

 

C

 

 

 

 

 

 

 

TASK 3

DETERMINING ACCELERATION FROM THE TICKER TAPE

  • Set up the experiment and produce a number of ticker tapes using a trolley running on an inclined runway.
  • Sample ticker tape

  • Discuss how to choose the interval for the initial and final velocities on the accelerated tape.

  • Discuss why the initial dots could be ignored (cut off).

  • Calculate initial and final velocities on the accelerated tapes.

  • Discuss how to obtain the time taken to change from initial to final velocity.

  • Calculate acceleration on the accelerated tapes.

 

Calculate acceleration for the tapes below, in the steps given. Take frequency f = 50Hz

 

 

 

A

The distance x = 18cm
The distance y = 30cm

Time for initial interval x or final interval y, t/s

 

Initial velocity, u/ms-1

 

Final velocity, v/ms-1

 

 

Time to change from average velocity u to average velocity v, T/s

 

Acceleration, a

 

B


The distance x = 14cm
The distance y = 24cm

Time, t

 

Initial velocity, u

 

Final velocity, v

 

Time, T

 

Acceleration, a

 

 

TASK 4

DETERMINING ACCELERATION DUE TO GRAVITY USING THE TICKER TIMER

  • Discuss the set up of the experiment.

  • Set up the experiment as shown in diagram and produce a number of ticker tapes.
  • Use the method of finding acceleration (from above) to determine the acceleration due to gravity.

 

Time for initial interval x or final interval y, t/s

 

Initial velocity, u

 

 

Final velocity, v

 

 

Time to change from average velocity u to average velocity v, T/s

 

Acceleration, a

 

 

 

Review your understanding

ITEM 1

 

Tape

Describe in each case how spacing between dots varies

Describe the type of motion represented

A

 

 

B

 

 

C

 

 

D

 

 

E

 

 

ITEM 2

The following examples show various tapes each of length 8cm got using a ticker timer of frequency 50Hz.
In each case find the time interval and the time interval of the tape and the velocity in ms-1.

 

Tape

Time interval

Velocity

A

 

 

B

 

 

C

 

 

Teachers' guide
Scheme of work
Student activity

Useful web links

Practical physics
Motion

Physics classroom

Fear of physics