Higher Physics
Revision tips and key areas
24th April
You will need paper, and a pen
Use the chat pod to ask questions
It’s all in the preparation!
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Make a study Planner
Share it with your parents
Trust it!
Review each topic
Sort LO’s into easy, hard, impossible!!!!
Share it with your parents
Move your phone and other devices into another room
Tell your parents what you’ve done
Review with notes and scholar
Past Papers
Make sure you keep the easy, easy
If you have time tackle the impossible
Projectiles
What would you like to learn?
Information from the question
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Initial Velocity of the golf ball
25 ms-1 at 37o above horizontal
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a) uhoriz = u cos Θ
uhoriz = 25 cos 37
uhoriz = 20 m s-1
(1)
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b) uvert = u sin Θ
uvert = 25 sin 37
uvert = 15 m s-1
(1)
Part c) Find maximum height of ball.
• What do we know?
• Vertically
u = 15 ms-1
a = -9.8 ms-2
s=?
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(4)
What else?
v=0
v2 = u2 + 2 as
02 = 152 + 2 x -9.8 x s
s = 11.5 m
Height of hilltop = 11.5 - 4 = 7.5 m
What would you like to learn?
Last part
This is about what we understand
Any value less than the 7.5 m, calculated in 1.c).
Justification; max height will be less since the frictional forces will reduce velocity of
ball more than before.
Or ball will reach highest point earlier in flight
Or time in air will be less
Or maximum height reached will be less
(2)
Forces
Two boxes on a smooth (frictionless) horizontal surface are joined together by a
short length of rope, as shown in the diagram below.
Box A has mass 2.1 kg and box B has mass 6.3 kg. Box B is being pulled by a
horizontal force of 14 N in the direction shown.
Calculate the acceleration of the blocks.
Calculate the tension in the rope connecting A and B.
Solutions
F = 14 N
m1 = 2.1 kg
m2= 6.3 kg
a = 1.7
m = 2.1
F=ma
14 = 8.4 x a
a = 1.7 ms-2
F = ma
F = 1.7 x 2.1
F = 3.5 N
Free body diagram
A skier, mass 80 kg, is skiing down a slope that is inclined at 38° to the horizontal.
The frictional force acting on the skier is 175 N.
Calculate the acceleration of the skier down the slope.
Result
Calculate the component of the skier's weight which acts in the direction parallel to
the slope, mgsinQ = 482.7 N
Fun = down slope + friction
=482.7 – 175
= 307.7
Fun = ma
307.7 = 80 x a
a = 3.8
Static Equilibrium
A child pushes a toy cart with a force F = 5.1 N. The force is applied at an angle of 15°
above the horizontal. The mass of the cart is 3.9 kg
Calculate the acceleration of the cart.
Calculate the kinetic energy of the cart when it is travelling at 3.1 m s-1.
Answers
Calculate the acceleration of the cart.
Fh = F cosQ
Fh = 5.1 cos 15
= 1.3 ms-2
Calculate the kinetic energy of the cart when it is travelling at 3.1 m s-1.
Ek = ½ mv2
= 0.5 x 3.9 x 3.12
= 19 J
Any Questions
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