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MOTION, SPEED, VELOCITY, MOMENTUM, and ACCELERATION. Velocity - speed in a direction Since velocity includes both speed and direction, if either value changes, velocity also changes.
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Velocity - speed in a directionSince velocity includes both speed and direction, if either value changes, velocity also changes.
General Velocity Equation: v = d twhere v is velocity d is distance t is time
Speed and Velocity • Velocity Equations: • v = d t vave = df – di tf - ti • Vector • speed in a direction • Speed Equations • s = d t save = df – di tf - ti • scalar
Speed and Velocity Questions • Car A travels from Nashville to Atlanta at a speed of 65 mph. Car B travels from Nashville to Montgomery at a speed of 65 mph. Are the velocities of the cars equal? Explain.
Speed and Velocity Questions • You turn on the radio and hear the tail end of a news story about a swarm of killer bees. The swarm, moving at a speed of 60 km/h, has just left a town 60 km north of your location. Should you be worried?
Speed and Velocity Questions • Suppose a lion moves due east so that it travels 25 km in 4 hr. A. What is the lion’s velocity? B. What is the lion’s speed?
Speed and Velocity Questions • Velocity v = d = 25 km = 6.2 km/hr east t 4 hr • Speed 6.2 km/hr
Speed and Velocity Questions • Why is it more important to know an airplane’s velocity than an airplane’s speed?
What are the two types of motion? The motion of an object can either be at a constant velocity or a changing velocity. A change in velocity is known as acceleration.
Acceleration Facts: - is defined as the rate of change of velocity - is a vector quantity - is measured in m/sec/sec or m/sec2
Acceleration Facts: - is a change in velocity. - is positive if velocity is increasing. - is negative if velocity is decreasing (also called deceleration). - occurs even when the speed stays the same and only the direction changes.
General Acceleration Equation: a = v twhere a is acceleration v is velocity or speed t is time
Acceleration Equation: a = v or vf - vi t t where v is delta v or change in velocity and means final velocity (vf) minus initial velocity (vi).
The metric system is now called the SI System. SI stands for International System of Units (abbreviated SI from the Frenchle Système international d'unités)
Symbols and SI Unitsspeed or velocity m/sec or m/sacceleration m/sec/sec or m/sec2distance mtime sec or s
Acceleration: Yes or No The red car is traveling at 20 mph on the winding mountain road.
Acceleration: Yes or No The red car is traveling at 20 mph on the winding mountain road.
Acceleration: Yes or No A camel walks a straight line at a constant speed.
Acceleration: Yes or No A camel walks a straight line at a constant speed.
Acceleration: Yes or No The car exited the freeway at speed of 55 mph and came to a stop before turning right onto a service road.
Acceleration: Yes or No The car exited the freeway at speed of 55 mph and came to a stop before turning right onto a service road.
Acceleration: Yes or No The space shuttle can travel at a speed of 17,500 km/hr.
Acceleration: Yes or No The space shuttle can travel at a speed of 17,500 km/hr.
What does the slope represent in the following graph? VELOCITY/SPEED
What does the slope represent in the following graph? ACCELERATION
Momentum - is the product of an object’s mass and velocity. - has the symbol p - is a vector quantity - equation p = mv where p is momentum, m is mass in kilograms, and v is velocity in meters/second- has the unit kgm s
Which has more momentum?(momentum = mass velocity) Baseball A0.62 kg5.3 m/s Baseball B0.62 kg4.1 m/s
What is the momentum of baseball A?(momentum = mass velocity) Baseball A0.62 kg5.3 m/s p = m vp = (0.62 kg)(5.3 m/s)p = 3.29 kgm s
Which has more momentum?(momentum = mass velocity) An empty dump truck traveling 35 mph An dump truck full of rocks traveling 35 mph
Which has more momentum?(momentum = mass velocity) An empty dump truck traveling 35 mph An dump truck full of rocks traveling 35 mph
What causes acceleration? A Force
What causes acceleration?(force = mass acceleration) Equation: F = m a
What causes acceleration?(force = mass acceleration) Equation: F = m aForce is measured in Newtons (N).
What causes acceleration?(force = mass acceleration) Equation: F = m aForce is measured in Newtons (N).1 Newton = 1 kg m/sec2
What causes acceleration?(force = mass acceleration) Equation: F = m aForce is measured in Newtons (N).1 Newton = 1 kg m/sec2
What causes acceleration?(force = mass acceleration) Equation: F = m aMass is measured in kg.Acceleration is measured in m/sec2
Problem: How much force is needed to accelerate a 714 kg sailboat that needs an acceleration of 2.5 m/sec/sec?
Problem: How much force is needed to accelerate a 714 kg sailboat that needs an acceleration of 2.5 m/sec/sec? F= m a F = 714 kg 2.5 m/sec/sec F = 1,785 N
F= m a W = m g weight = mass times gravityWeight is a force.Gravity is a constant. (9.8m/sec2)
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