Physics Final Exam Review

True or False? The horizontal component of a projectile's velocity is independent of the vertical component

Answer TRUE

After a rock that is thrown straight up reaches the top of its path and is starting to fall back down, its acceleration is (neglecting air resistance) __?___

Answer 10 m/s 2 which is gravity (pulling downward)

A plane flying north at 50 km/h experiences a wind 10 km/h south. What is the magnitude and direction of the plane?

Answer This is a headwind; therefore, you subtract. The answer is 40 km/h going north

A plane flying north at 50 km/h experiences a wind 10 km/h east. What is the magnitude and direction of the plane?

Answer Use Pythagorean Theorem a 2 + b 2 = c 2 The answer is 51 km/h northeast

When an object is thrown in a curved path, what is its velocity at the top of the path?

Answer Entirely horizontal because the vertical component is zero

Assuming the car starts from rest, what is the acceleration if the car has a speed of 20 m/s for 4 s?

Answer Unknown a Known v = 20 m/s t = 4 s a = v/t 5 m/s 2

How high is a tree if an acorn falls and hits the ground in 2.25 s?

Answer Unknown d = v o t + ½ gt 2 d Known = 0(2.25s) + ½ (10m/s 2 )(2.25s) 2 t = 2.25 s = 0 + 5m/s 2 (5.0652s 2 ) d = m

Question When a balloon deflates, the balloon pushes on the air and _______.

Answer The air pushes on the balloon

Question A book weighs 10 N. When held at rest in your hands, the net force on the book is ____.

Answer Zero

Question As a ball falls, the action force is the pull of Earth's mass on the ball. What is the reaction to this force?

Answer The pull of the ball’s mass on the Earth

Question The outside force that slows objects down or stops their motion is ___.

Answer Friction

Question What is the pressure exerted on a table by a book that weighs 35 N and covers an area of 3 m 2 ?

Answer Known F = 35 N A = 3 m 2 Unknown P Equation P = F A Solve P = 35 N 3m 2 P = N/m 2 or Pa

Question A dog walks on a street. What is the force of friction between the 225 N dog and the street that has a coefficient of friction of 0.26?

Answer Known w = 225 N = F N µ = 0.26 Unknown F f = ? Equation F f = µF N Solve F f = µF N F f = (0.26)(225N) F f = 58.5 N

Question Mass and acceleration are __________________ proportional.

Answer Inversely proportional –More mass results in less acceleration –Less mass results in more acceleration

Question Pressure and Area are _______________ proportional.

Answer Inversely proportional –More area covered results in less pressure –Less area covered results in more pressure

Question Which has greater tangential speed, a horse near the outside rail of a merry-go- round or a horse near the inside rail?

Answer The one on the outside because it has a larger radius

a.depth of the measuring point b.mass of the liquid c.volume of the liquid d.density of the liquid e.both A and D ____1.Pressure in a liquid depends on the _____.

Answer E The depth and the density

a.weight of the fluid displaced b.mass of the fluid displaced c.volume of the fluid displaced d.mass of the object e.none of the above Archimedes' principle says that an object is buoyed up by a force that is equal to the _____.

Answer A weight of the fluid displaced

What is the difference in water pressure between the top and bottom of a 100-m deep well?

Answer At the bottom the pressure is greater

If you lift four loads up one step, how much work do you do compared to lifting two loads up one step.

Answer You do twice as much work W = Fd, therefore, if the distance stays the same but you lift twice as much weight, you do twice as much work

What is the buoyant force of a rubber ducky floating in water that displaces 0.05 cm 3 of water. (remember the density of water is 1 g/cm 3 )

Answer Known D = 1 g/cm 3 g = 10 m/s 2 V = 0.05 cm 3 Unknown F b Equation F b = DgV Solve F b = DgV =(1g/cm 3 )(10m/s 2 )(0.05cm 3 ) F b = 0.5 N

Draw a parallel and series circuit with three resistors. Label the resistors, wire and battery.

Answer SeriesParallel wire battery

The Tacoma Bridge collapsed due to the alignment of frequencies between the bridge and the wind which is called ___.

Answer Resonance

Which is the angle of reflection?

– Angle C

Which is the angle of reflection?

Which is the angle of incidence? – Angle B