Physics Pretend-to-be-Jeopardy

Final Jeopardy Graphing Physics Life at NSAA Fantastic Forces Everyday Stuff Time to Fly

Everyday Stuff I saw an orange fall from a tree. What was it’s acceleration?

Everyday Stuff Answer 9.8 m/s 2

Everyday Stuff A raindrop falls from the sky. It starts from rest somewhere in the clouds. It hits the floor at 100 m/s. How far did the drop fall?

Everyday Stuff Answer 510 m vf2= vi2 + 2a∆x

Everyday Stuff Yesterday I saw people on TV trying to sound smart using this problem: Train A leaves the station traveling at 20 m/s. Train B leaves the station traveling at 35 m/s. Both trains travel at a constant velocity. Stations A and B are 175 m apart. After how many seconds do the trains cross paths, assuming they are traveling to the opposite station?

Everyday Stuff Answer We know that they are at the same location when the cross, so final positions are equal. AB x f = x i + vt x i + vt = x i + vt 0m + (20m/s)t = 175m + (-35m/s)t (55m/s)t = 175m t = 3.18s

Everyday Stuff A student wanted to find out if the temperature of water affected the amount of sugar that would dissolve in it. He put 50 mL of water into each of four identical jars. He changed the temperatures of the water in the jars until he had one at 0°C, one at 50°C, one at 75°C, and one at 95°C. He then dissolved as much sugar as he could in each jar by stirring. What is the relationship being studied?

Everyday Stuff Answer The effect of higher temperature on the amount of sugar dissolved.

Everyday Stuff a

Everyday Stuff Answer a

Everyday Stuff In Physics, what are the standard units for measuring 1. Time 2. Distance 3. Velocity 4. Acceleration

Everyday Stuff Answer 1. Time: seconds (s) 2. Distance: meters (m) 3. Velocity: m/s 4. Acceleration: m/s 2

Launching Things! 100

Launching Things! Answer a

Launching Things! 200 a

Launching Things! Answer a

Launching Things! 300 A diver running at 3.6 m/s dives out horizontally from the edge of a cliff and reaches the water below 2.5 s later. How high was the cliff?

Launching Things! Answer m

Launching Things! 400 A ball player wishes to determine her pitching speed by throwing a ball horizontally from an elevation of 4.0 m above the ground. She sees the ball land 25. m down range. Determine the speed of the ball as it leaves her hand

Launching Things! Answer 27.8 m/s

Launching Things! 500 A daredevil tries to jump a canyon of width 10 m. To do so, he drives his motorcycle up an incline sloped at an angle of 15 degrees. What minimum speed is necessary to clear the canyon?

Launching Things! Answer m/s Click here for solution

Launching Things! 600 A long jumper leaves the ground with an initial velocity of 12 m/s at an angle of 28-degrees above the horizontal. Determine the time of flight, the horizontal distance, and the peak height of the long-jumper.

Launching Things! Answer Flight Time: 1.1 seconds Horizontal Distance: 12.2 meters Peak Height: 1.6 meters click here for solution

Graphing!!! 100 Do the cyclists start at the same point? How do you know? If not, which is ahead?

Graphing!!! Answer No… Cyclist B starts ahead. The y-intercept gives his position at time = 0s… or the start.

Graphing!!! 200 Determine the object's average velocity. Determine the object's position at t = 10

Graphing!!! Answer 5 m/s Avg Velocity: 5 m/s 60 m At t=10s, will be at 60 m

Graphing!!! 300 Determine the displacement for the first three seconds for each object. Object WObject J

Graphing!!! Answer Object W9 meters Object J9 meters Go figure…. Go figure….

Graphing!!! 400 Position (m) Time (s) Here is a position v. time graph for an object. Would it be more accurate to describe the velocity in terms of average velocity or instantaneous velocity? How would you find the one you choose?

Graphing!!! Answer Instantaneous Velocity Draw a tangent line at a specific point. The slope of that tangent line will be the velocity at that instant in time.

Graphing!!! 500 Sketch a(1) velocity v. time graph and (2) acceleration v. time graph x t A B D E F G C Position (m) Time (s)

Graphing!!! Answer Velocity v. Time Acceleration v. Time A B C D E F G

Graphing!!! Assume that the ball does not experience any change in velocity while it is on a horizontal portion of the rail. Produce the following graphs: (1)Position v. Time, (2) Vel. v. Time, (3) Accel. v. Time

Graphing!!! Answer Acceleration Velocity Position

Physics Life at NSAA 100 A very scared senior that was just caught ditching is running from Mr. Walker. The student accelerates from rest to a speed of 28 m/s in 20 s. (Apparently fear makes you go fast.) What is the acceleration of the senior?

Physics Life at NSAA Answer 1.4 m/s 2 v f = v i + a ∆ t

Physics Life at NSAA 200 A student really needs to use the restroom in class but the teacher won’t let him go for 15 minutes. After the 15 mins are up, the student, starting from rest, accelerates at a rate of 6.0 m/s 2. If the restroom door is 16 m away, how fast will the student be going as he reaches the door?

Physics Life at NSAA Answers 13.9 m/s v f 2 = + v i 2 + 2a ∆ x

Physics Life at NSAA 300 A dancer is practicing for winter performance. She has her I-pod in and is not paying attention. Starting from rest, she moves across the stage accelerating at a constant 1.0 m/s 2. She plans on continuing to move that way until the song is over in 6s. The stage is 15m wide. Is she going to fall off the stage?

Physics Life at NSAA Answer Yep…. She won’t stop for 18m. Moral of the story: Pay attention.

Physics Life at NSAA 400 A skateboarder is skating at a velocity of 6 m/s when a wheel falls off causing him to slow down at a uniform rate of 0.5m/s 2. How fast will he be skating after going an additional 13 meters?

Physics Life at NSAA Answer 4.8 m/s v f 2 = + v i 2 + 2a ∆ x Moral of the Story: Take care of your stuff.

Physics Life at NSAA 500 A student wants to show off her freshly restored 1967 Shelby Mustang. She burns out of the parking lot going from rest to 36 m/s (≈60mph) in 4 seconds. The car's velocity changes at a constant rate. What is the car’s acceleration? How fast will the car be going 3.0 seconds after it starts?

Physics Life at NSAA Answer 9 m/s 2 v f = v i + a ∆ t 27 m/s

Physics Life at NSAA 600 A guy wants to scare his friend. He drives a car at a constant speed of 25 m/s directly at his friend, with the intention of stopping just before him. His friend is 150 m away when the driver hits the brakes and beings to accelerate uniformly at a rate of 0.63m/s 2. Will the car come to a stop as the driver intended, or should we call an ambulance?

Physics Life at NSAA Answer The friend is safe. (Solve for the distance he went if his final velocity is 0 m/s, his initial velocity is 25 m/s, his acceleration is m/s2.) The driver stopped after 99.2 m….. 0.8m short. v f 2 = + v i 2 + 2a ∆ x If you try to solve for the final velocity at 100m you will end up having to take the square root of a negative number (it wont work.. Because he had no velocity at 100 m/s)

Forces 100 A 4600 kg helicopter accelerates upward at 2.0 m/s2. What lift force is exerted by the air on the propellers?

Forces Answer N F L : Force lifting helicopter off ground ΣF = F L – F E = ma F L – (4600kg)(9.8N/kg) = (4600kg)(2m/s2) F L = 9200 N N F L = N

Forces 200 A race car has a mass of 710 kg. It starts from rest and travels 40.0m in 3.0s. The car is uniformly accelerated during the entire time. What net force is acting on the car?

Forces Answer 6305 N (1) Find Acceleration xf = xi + vit + ½ at 2 (2) Find Net Force ΣF = ma

Forces 300 A 65 kg person dives into the water from the 10 meter high platform. a)What is her speed as she enters the water? b)She comes to a stop 2.0 m below the surface of the water. What net force did the water exert on the swimmer?

Forces Answer 14 m/s, 3185 N vf 2 = vi 2 + 2a∆x ΣF = ma

Forces 400 Suppose that a 1000 kg car is traveling at 25 m/s (≈55 mph). Its brakes can apply a force of 5000N. What is the minimum distance required for the car to stop?

Forces Answer 62.5 m Find Acceleration ΣF x = max Find Distance vf 2 = vi 2 + 2a∆x

Forces 500 A 10 kg block is allowed to slide down a ramp with u k = a. What is the value of the frictional force opposing the block's slide down the ramp? b.What is the acceleration of the block?

Forces Answer F k = 13.8 N a = 1.97 m/s 2

Forces 600 A 70.0 kg box is pulled across a frictionless surface by a 300. N force at an angle of 30.° to the horizontal. What is the acceleration of the box in the x-direction? What is the normal force on the box?

Forces Answer a x = 3.71 m/s 2 F N = 536 N

Final Jeopardy

Final Jeopardy - Answer …….