Two cars with different masses travel at the same speed down a hill toward a stop sign. What will happen when both cars apply brakes at the same time to stop? F.The car with the smaller mass will require less force to stop than the car with the larger mass G.The car with the larger mass will maintain its velocity while traveling down the hill. H.The car with the smaller mass will take longer to Stop than the car with the larger mass. J. The car with the larger mass will have less inertia than the car with the smaller mass. A 100
F = ma The smaller the mass, the faster it can stop A 100
A 200 Four students raced toy cars on a track. The mass and the acceleration of each car is recorded in the table below. Which toy car had the greatest applied force?
A 200 Work all problems: 1 =.19 x 2 =.38N 2 =.15 x 3 =.45 N 3 =.25 x 1.5 =.375 N 4 =.21 x 2.5 =.53 N
An object will continue moving in a straight line unless it is acted on by an unbalanced force. Which of the following best explains Earth’s motion? A.There is no unbalanced force acting on Earth because space is empty and nothing touches Earth. B. The gravitational force pulling Earth toward the sun is equal and opposite to the force pulling the sun toward Earth, so there is no unbalanced force acting on Earth. C.The sun moves in an elliptical orbit around Earth, and the sun’s gravity pulls Earth along. D.Earth moves in an elliptical orbit around the sun because the gravitational force of the sun attracts Earth. A 300
D The Earth would move in a straight line through space if the sun’s gravity did not keep it in orbit. A 300
A 400 Some students measure the acceleration of a wheeled cart being acted on by varying forces. The students record their data in the table shown above. According to the data table, how much force is acting on the cart when the students measure an acceleration of 2.6 m/s 2 ? (find the mass from the given data, then find the force for the last one.)
m = f/a M = 5/1 = 5 grams F = ma = 5 x 2.6 = 13 A 400
A 500 Sometimes tectonic plates do not move easily past one another, and the plates become stuck. Forces build up, and when the plates finally move, tension is released, as shown above. The sudden movement of the plates is caused by: * The mass of the plates * the weight of the plates Unbalanced forces Gravitational forces
Which of the following is considered to be work? A body builder lifts 350 pounds above his head. A mother carries her baby from room to room. A woman carries a 20 km grocery bag to her car? A body builder holds 350 pounds over his head for 5 minutes B 100
A body builder LIFTS 350 lbs over his head. Work is moving a FORCE through a DISTANCE. When he holds it over his head, he is not moving it through a distance. B 100
B 200 Calculate: If a man pushes a concrete block 10 meters with a force of 20 N, how much work has he done?
W = f x d = 20 N x 10 m = 200 Newton-meters (Joules) B 200
B 300 The diagram shows a boat moving NORTH in a river at 3m/s while the current in the river moves SOUTH at 1 m/s. How will the boat be affected if it enters a part of the river where the current is moving south at 2 m/s? *The boat will move slower *The boat will move faster *The boat will stop *The boat will move to the west
This is a simple force problem 3 m/s North minus 2 m/s South (subtract forces going in opposite directions) equals 1 m/s North. The boat will be moving slower than it was before, when it was moving North at 2 m/s (3m/s N – 1 m/s S = 2 m/s N) B 300
B 400 Which of the following situations shows work being done? A. Student sitting in chair holding both boxes B.Student holding the large box 1 m above the floor C.Student standing and holding the small box. D.Student lifting the small box 0.5 m from the floor to a table.
.5 m x 1.3N =.65 N-m (Joules) Work is done only in D. None of the others move a force through a distance. B 400
B 500 Which best explains the student’s data? F.The speed of the cart DECREASES as the cart rolls down the ramp because of FRICTION between the cart and the ramp. G.The speed of the cart INCREASES as the cart rolls down the ramp because the force acting on the cart is GREATER than the force of GRAVITY. H.The speed of the cart INCREASES as the cart rolls down the ramp because the forces acting on the cart are UNBALANCED.
The force pulling the cart down the ramp IS gravity, not a force GREATER than gravity, as in answer G. The cart is clearly INCREASING speed, not DECREASING, as in F. B 500
. C 100 In the classroom demonstration shown below, a rubber ball is dropped from position 1. The ball bounces as shown. At which position does the ball have both the greatest potential energy and the least kinetic energy? Position 1 Position 2 Position 3 Position 4
Position 1. Potential energy is stored energy; Kinetic energy is energy of motion. The ball will fall farthest and pick up most acceleration from position 1 C 100
What do we call energy sources that cannot be replaced, such as oil, coal, gas, and other fossil fuels? C 200
D Propane is a potential energy. It is a chemical which can be turned into heat (thermal energy) by burning; the mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and position of an object; the balloon rises, turning the potential energy into kinetic energy, thus, mechanical energy. C 400
C 500 Why does Earth get more energy from the sun than from all the other stars in the universe combined? A.The sun is much larger than the other stars B.The sun is much hotter than the other stars C.The sun is much more dense than the other stars D. The sun is much closer than the other stars
D The sun is our closest star. It is the only one close enough to receive heat energy from. C 500
D 100 A car travels at a constant speed of 15 m/s for 2 minutes. The car increases its speed from 15 to 25 m/s during the next minute and then travels at a constant speed of 25 m/s for 2 more minutes. Which of the following graphs best represents the car’s motion during this 5-minute period?
A student walks 2 km in 30 minutes. What is the student’s average speed in km/h? D 200
30 minutes =.5 hour Watch your units!!! 4 km/hour D 200
D 300 The 3 vehicles shown are all traveling at a speed of 15 m/s, but only the pickup truck has a changing velocity. The pickup truck has a changing velocity because it: A. can accelerate faster than the other two vehicles B. Is traveling in the opposite direction from the other two vehicles C. Is traveling on a curve in the road D. Needs a large amount of force to move
C An object accelerates when it SPEEDS UP, SLOWS DOWN, or CHANGES DIRECTION. The truck is going through a curve— changing direction. D 300
What is the speed (per hour) of a car traveling 144 km in 90 minutes? ________________ km/h D 400
Km/hour: How many hours are in 90 minutes? There are 60 minutes in 1 hour; therefore 90 minutes equals 1.5 hours 144 km = 96 km/h 1.5 hours D 400
D 500 What is the average speed of the bass boat? Time (seconds ) Distance (meters) 125 100 85 65 50 20 0
S = D/T 125m divided by 10 seconds = 12.5 m/s D 500
E 100 Earth would not have seasons if it: A.No longer tilted on its axis B.Stopped rotating on its axis C.Took an additional month to orbit the sun D.Revolved around the sun in the opposite direction
A. Earth’s seasons are caused by 2 factors: the tilt on its axis and its revolution around the sun. E 100
This is a trait that seems to disappear and only shows up if received from BOTH parents. E 200
What is the following: TT Homozygous recessive Heterozygous Homozygous dominant E 400
Homozygous Dominant Both are capital – dominant Both are the same - homozygous E 400
What is the ratio of offspring that will end up with a homozygous recessive trait? E 500
1:4 (same as 25%) Three boxes have at least one capital letter—those will exhibit dominant traits. One box has two lower case letters – homozygous recessive E 500
F 100 A student builds a model based on this diagram. The student uses foam balls to represent the Earth and the moon and a flashlight to represent the Sun. From which position should the student shine the flashlight?
The new moon is always between the Earth and the Sun. Position 4 F 100
F 200 A student keeps a record of the phases of the moon for one month (like you all did!!) On the first night of the student’s observations, the full moon is visible in the sky. After the full moon, which of these phases will the student observe next? * Waxing crescent moon Waxing gibbous moon Waning crescent moon Waning gibbous moon
This is a pattern of weather that occurs in a particular area over many years. F 400 Which topographic map fits the picture most correctly?
A – the steeper slope on the left has contour lines that are close together; the gently sloping bank on the right has widely spread contour lines. F 400
F 500 In the above picture, primary succession occurs when the a.Grasses begin to grow on the newly formed island b.Woody plants begin to grow, following the growth of grasses c.Woody plants begin to grow on the newly formed island d.Grasses begin to grow, following the growth of woody plants