Linear Motion klb physics form 3 notes pdf

KLB PHYSICS FORM 3 NOTES PDF

Linear Motion klb physics form 3 notes pdf

Linear Motion klb physics form 3 notes pdf 1024 670 refilwe

LINEAR MOTION KLB PHYSICS FORM 3 NOTES PDF: Study of motion is divided into two;

1. Kinematics

2. Dynamics

In kinematics forces causing motion are disregarded while dynamics deals with motion of objects and the forces causing them.

I. Displacement

Distance moved by a body in a specified direction is called displacement. It is denoted by letter‘s’ and has both magnitude and direction. Distance is the movement from one point to another. The Si unit for displacement is the metre (m).

II. Speed

This is the distance covered per unit time.

Speed= distance covered/ time taken. Distance is a scalar quantity since it has magnitude only.

The SI unit for speed is metres per second(m/s or ms-1)

Average speed= total distance covered/total time taken Other units for speed used are Km/h.

Examples

1. A body covers a distance of 10m in 4 seconds. It rests for 10 seconds and finally covers a distance of 90m in 60 seconds. Calculate the average speed.

Solution

Total distance covered =10+90= 100m

Total time taken =4+10+6= 20 seconds

Therefore average speed = 100/20= 5m/s

2. Calculate the distance in metres covered by a body moving with a uniform speed of 180 km/h in 30 seconds.

Solution

Distance covered=speed*time

=180*1000/60*60=50m/s

=50*30

=1,500m

3. Calculate the time in seconds taken a by body moving with a uniform speed of 360km/h to cover a distance of 3,000 km?

Solution

Speed:360km/h=360*1000/60*60=100m/s

Time=distance/speed

3000*1000/100

=30,000 seconds.

III. Velocity

This is the change of displacement per unit time. It is a vector quantity.

Velocity=change in displacement/total time taken

The SI units for velocity are m/s

READ  form 3 past papers with answers 2021-2020 Pdf

Examples

1. A man runs 800m due North in 100 seconds, followed by 400m due South in 80 seconds. Calculate,

a. His average speed

b. His average velocity

c. His change in velocity for the whole journey

Solution

a. Average speed: total distance travelled/total time taken

=800+400/100+80

=1200/180

=6.67m/s

b. Average velocity: total displacement/total time

=800-400/180

=400/180

=2.22 m/s due North

c. Change in velocity=final-initial velocity

= (800/100)-(400-80)

=8-5

=3m/s due North

Source: https://www.advance-africa.com/Physics-Notes-Form-3.html

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