Page 2 - CLASS VII Lesson Notes Forces and Energy
P. 2
2. A parachute opening:
o Air resistance > weight → slows the object down.
o Later, air resistance = weight → object falls at constant speed.
3. Tennis ball hit by racket:
o Force from racket > force from ball → ball changes direction.
4. Planets orbiting the Sun:
o Gravity constantly pulls them toward the Sun.
o This unbalanced force keeps them moving in a circle.
Force Diagrams:
• Use arrows to show:
o The direction the force is acting.
o The size of the force (longer arrow = stronger force).
Situation Balanced/Unbalanced Result
Equal forces in opposite Balanced No change in motion
direction
Unequal forces in opposite Unbalanced Speeds up or slows down
direction
Equal forces not opposite Unbalanced Change in direction
Unequal and not opposite Unbalanced Change in speed and direction
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