Presentation is loading. Please wait.

Presentation is loading. Please wait.

PASS Content Standard 2.1 Objects change their motion only when a net force is applied. Laws of motion are used to determine the effects of forces on the.

Similar presentations


Presentation on theme: "PASS Content Standard 2.1 Objects change their motion only when a net force is applied. Laws of motion are used to determine the effects of forces on the."— Presentation transcript:

1 PASS Content Standard 2.1 Objects change their motion only when a net force is applied. Laws of motion are used to determine the effects of forces on the motion of objects.

2

3

4 Motion - 12 min

5

6

7

8 Earth rotates on its axis at 1,100 mph Earth orbits the Sun at 68,000 mph

9 The whole galaxy rotates at 490,000 mph

10

11

12 Two Dimensional World

13

14

15 Speed= distance time

16 Speed= distance time A snail crawls 10 feet in 5 minutes. What is the speed of the snail? = 10 feet 5 minutes =2 feet/min

17

18 Average speed= total distance total time

19 Average speed= total distance total time A boy runs 1 mile in 6 minutes, rests for 2 minutes, then walks 1 mile in 12 minutes. What is his average speed? = 1 mile + 1 mile 20 minutes = 2 miles 20 minutes

20

21 Distance (meters) Time (seconds)

22

23 is a vector quantity because it has both speed and direction.

24 Vectors - 12 min

25 All these planes have the same speed. How is their velocity different?

26 The length of the line represents the quantity (speed) and the arrow indicates the direction. Add vectors head to tail.

27 Direction is indicated by compass degrees

28 The magnitude of the speed is indicated by the measured length (scale) of the line.

29

30 0o0o 90 o 180 o 270 o An airplane is flying 200 mph at 50 o. Wind velocity is 50 mph at 270 o. What is the velocity of the plane?

31 0o0o 90 o 180 o 270 o

32 0o0o 90 o 180 o 270 o

33 0o0o 90 o 180 o 270 o

34 0o0o 90 o 180 o 270 o

35 0o0o 90 o 180 o 270 o

36

37

38

39

40

41 Acceleration = Velocity (final) - Velocity (original) time

42 A car traveling at 60 mph accelerates to 90 mph in 3 seconds. What is the car’s acceleration?

43 Acceleration = Velocity (final) - Velocity (original) time A car traveling at 60 mph accelerates to 90 mph in 3 seconds. What is the car’s acceleration? = 90 mph - 60 mph 3 seconds = 30 mph 3 seconds = 10 mph/second

44

45 A car traveling at 60 mph slams on the breaks to avoid hitting a deer. The car comes to a safe stop 6 seconds after applying the breaks. What is the car’s acceleration?

46 Acceleration = Velocity (final) - Velocity (original) time A car traveling at 60 mph slams on the breaks to avoid hitting a deer. The car comes to a safe stop 6 seconds after applying the breaks. What is the car’s acceleration? = 0 mph - 60 mph 6 seconds = - 60 mph 6 seconds = - 10 miles per hour per second

47

48

49

50

51 Acceleration toward the center of a circular path.

52 For an object to travel in a curved path, some force must be accelerating it toward the center of the circle.

53

54 Force provided by engine Acceleration provided by tires

55 What happens if the accelerating force is removed?

56 The object moves in a straight line.

57 An apparent force that appears only in rotating frames of reference.

58 This “false” force appears to push away from the center of the circular path.

59 If you are riding in the passenger seat of this car, what do you feel?

60 What's actually happening?

61

62 Aristotle and Newton had different ideas about forces and motion. Aristotle's idea: For an object to move at a constant speed, a constant force must be applied. Newton's idea: An object moving at a constant speed will continue at that speed without additional force being applied.

63

64 Produce NO Motion

65 Produce Motion

66

67 Sliding - two solid surfaces rubbing against each other. Rolling - an object rolling over a surface. Fluid - an object moving through a fluid.

68

69 Newton’s Laws - 5 min

70 An object at rest will remain at rest, and a moving object will remain at a constant velocity unless acted on by unbalanced forces.

71 Force = mass X acceleration F = Ma

72 For every action, there is an equal and opposite reaction.

73 Rockets - 6 min

74

75

76 Momentum - 8 min

77 Does a long pendulum swing faster than a short one?

78 Does a heavy pendulum swing faster than a light one?

79

80

81 The total momentum of any group of objects remains the same unless acted on by outside forces.

82 Elastic - occur when both momentum and kinetic energy are conserved. Inelastic - occur when momentum is conserved, but kinetic energy is not.

83 M 1 V 1 = M 2 V 2 Before After

84 Colliding objects have same mass Elastic Collision

85 Heavy object strikes light object Elastic Collision

86 Light object strikes heavy object Elastic Collision

87 Inelastic Collision Colliding objects have same mass

88

89

90 Rollercoasters - 4 min

91

92

93 Units of Force are Newtons Units of Distance are Meters Newton Meters = Joules

94 Work - 2 min

95 A force of 200 Newtons is used to move an object 10 meters. How much work is done?

96 A force of 200 Newtons is used to move an object 10 meters. How much work is done? W = Fd

97 A force of 200 Newtons is used to move an object 10 meters. How much work is done? W = Fd = (200 N)

98 A force of 200 Newtons is used to move an object 10 meters. How much work is done? W = Fd = (200 N)(10 meters)

99 A force of 200 Newtons is used to move an object 10 meters. How much work is done? W = Fd = (200 N)(10 meters) = 2000 Joules

100 Units of Work are Joules Joules per second = Watts Power is the rate at which work is done.

101 power - 2 min

102 A machine produces 250 joules of work in 2 seconds. How much power is produced?

103 A machine produces 250 joules of work in 2 seconds. How much power is produced? P = W / t

104 A machine produces 250 joules of work in 2 seconds. How much power is produced? P = W / t = (250 joules)

105 A machine produces 250 joules of work in 2 seconds. How much power is produced? P = W / t = (250 joules) / 2 sec

106 A machine produces 250 joules of work in 2 seconds. How much power is produced? P = W / t = (250 joules) / 2 sec = 500 Watts

107

108

109

110

111

112

113

114

115

116 1 Horsepower is equal to 745.56 Watts or 550 ft lb/sec

117

118

119

120

121

122

123

124 The effort force is applied to a machine.

125 The resistance force is applied by a machine.

126 The number of times a machine multiplies the effort force.

127 Work output Work input X 100

128 Inclined Plane

129 An 800 pound motorcycle is rolled up a 10 foot ramp into a pickup bed that is 3 feet off the ground. Calculate input work. Calculate output work. Calculate efficiency %.

130 Work input = 10 ft X 800 lb = 8000 ft lb Work output = 3 ft X 800 lb = 2400 ft lb

131 Work output Work input X 100 % Efficiency = 2400 ft lb 8000 ft lb X 100 0.3 X 100 = 30% Efficiency

132 Length Height = Mechanical Advantage = 10 ft 3 ft = 3.33 mechanical advantage

133 Machines make work

134 easier or faster...

135 but machines NEVER

136 produce more work

137 than is put into them.

138 In fact, because of friction,

139 more work goes

140 into a machine

141 than comes out.

142 Climbing cars - 24 min

143

144 In 1868, a motion was passed in congress to abolish the U.S. Patent Office because all important discoveries had already been made.

145

146

147

148 Make work easier because the effort force moves over a greater distance than the resistance force.

149 Inclined Plane - 2 min

150 Force is multiplied since it is applied to a wide area and exerted over a small area.

151 Wedge - 2 min

152 Multiplies an effort force by acting through a long effort distance.

153 Screw - 1 min

154 A bar which moves freely around a fixed position, or fulcrum.

155 Levers - 3 min

156 Three Parts of a Lever Effort Force Resistance Force Fulcrum

157

158 The Fulcrum is between the Effort Force and the Resistance force

159 Multiplies Effort Force and changes its direction

160

161 The Resistance is between the Effort Force and the Fulcrum

162 Multiplies the Effort Force but does not change its direction

163

164 The Effort Force is between the Resistance Force and the Fulcrum

165 Does not multiply the Effort Force and does not change its direction.

166 Does not multiply the Effort Force and does not change its direction. What DOES it do??

167

168 Direction of the Effort Force is changed. Mechanical Advantage = 0

169 Direction of the Effort Force is not changed. Mechanical Advantage = 1

170 Direction of the Effort Force is changed. Mechanical Advantage is equal to the number of supporting ropes.

171 Pulleys - 1 min

172 A fixed pulley does not have a mechanical advantage. Fixed pulleys only change the direction of the force.

173 A movable pulley has a mechanical advantage. The effort force is in the direction of the movement of the resistance.

174 Two wheels of different sizes connected - the axle being the smaller wheel.

175 Wheel & Axle - 1 min

176 Worm Gear

177

178

179

180 Compound Machines - 4 min

181

182

183

184

185

186


Download ppt "PASS Content Standard 2.1 Objects change their motion only when a net force is applied. Laws of motion are used to determine the effects of forces on the."

Similar presentations


Ads by Google