25 pt. 5 pt. 10 pt. 15 pt. 20 pt. 25 pt. 5 pt. 10 pt. 15 pt. 20 pt. 25 pt. 5 pt. 10 pt. 15 pt. 20 pt. 25 pt. 5 pt. 10 pt. 15 pt. 20 pt. 25 pt. 5 pt. 10 pt. 15 pt. 20 pt.

1-25 The graph below is a velocity vs time graph. What is the distance covered in the first 10 seconds? Time (s) Velocity (m/s)

1-25A Time (s) Velocity (m/s) Calculate the area under the graph for the first 10 seconds. Area = 310 m/s*s or 310 m

What is the acceleration of a car that goes from 0 to 100 m/sec in 2 minutes? (answer in m/sec 2 )

2-20A a =  v / t and, t = 2 min (60sec/min) = 120 sec so… a = (100m/s - 0m/s)/120 sec a = m/sec 2 What is the acceleration of a car that goes from 0 to 100 m/sec in 2 minutes? (answer in m/sec 2 )

1-15 A dragster accelerates down the track at a constant rate. It starts from rest and crosses the finish line moving at a speed of 250 mph. What is its average velocity?

3-5A A dragster accelerates down the track at a constant rate. It starts from rest and crosses the finish line moving at a speed of 250 mph. What is its average velocity? v avg = (v i + v f )/2 v avg = (250mph + 0mph)/2 v avg = 125 mph

How far would a sprinter run if they start at rest and end the race moving at a velocity of 20 m/sec? Assume they run for 10 seconds.

3-25A How far would a sprinter run if they start at rest and end the race moving at a velocity of 20 m/sec? Assume they run for 10 seconds. v avg = (v i + v f )/2 v avg = (20m/sec + 0m/sec)/2 = 10 m/sec d = v avg t = (10m/sec)(10sec) d = 100 meters

3-20 How much time would it take to run 100 meters if you start at 10m/s and accelerate at 2 m/sec 2 ?

3-20A How much time would it take to run 100 meters if you start at 10m/s and accelerate at 2 m/sec 2 ? d = v i t + 1 / 2 at 2 100m = 10m/s*t + 0.5*2m/s 2 *t 2 Use quadratic formula t = 6.18 seconds

2-20 You and a friend push a heavy crate across the floor at a constant speed. If you push with a combined force of 100 N, how hard is friction pushing back on the crate? A) less than 100 N B) 100 N exactly C) more than 100 N D) not enough info

2-20A You and a friend push a heavy crate across the floor at a constant speed. If you push with a combined force of 100 N, how hard is friction pushing back on the crate? A) less than 100 N B) 100 N exactly C) more than 100 N D) not enough info F f = 100 N F pull = 100 N

3-10A What is the weight of a 50-kg object as it falls at a speed of 100 m/sec in a vacuum chamber?

3-10A The speed of the object has no effect on its weight, so… W = mg = (50 kg)(9.8 m/sec 2 ) W = 490 Newtons What is the weight of a 50-kg object as it falls at a speed of 100 m/sec in a vacuum chamber? FgFg

3-20A A 2000-kg car accelerates down the road. The friction from the road drives it with a force of 5000 N, and air drag is 1400 N. What is the car’s acceleration?

3-20A F net = ma and F net = 5000 N – 1400 N So… F net = 3600 N = (2000 kg)a a = 3600 N/2000 kg = 1.8 m / sec 2 FfFf FfFf A 2000-kg car accelerates down the road. The friction from the road drives it with a force of 5000 N, and air drag is 1400 N. What is the car’s acceleration?

3-25A A 75-kg parachutist is falling through the air – while experiencing an air drag of 200 N. If they fall from rest for 10 seconds in this manner, how fast are they moving?

3-25A v f = at so we must find a… F net = Weight – Drag = ma (75 kg)(9.8 m / s 2 ) – 200 N = (75 kg)a 535 N/75 kg = 7.13 m / s 2 = a v f = at = (7.13 m / s 2 )(10 sec) = 71.3 m / s A 75-kg parachutist is falling through the air – while experiencing an air drag of 200 N. If they fall from rest for 10 seconds in this manner, how fast are they moving? FfFf FgFg

2-25 In space, a rocket of mass 250-kg is pushed by a thrust force of 10,000-N through 12 kilometers. How fast is it moving when the engine shuts off?

2-25A F = ma 10,000N = 250kg * a a = 40m/s 2 v f 2 = v i 2 + 2ad v f 2 = *40m/s 2 *12,000m v f = 980 m/sec In space, a rocket of mass 250-kg is pushed by a thrust force of 10,000-N through 12 kilometers. How fast is it moving when the engine shuts off?

A What is the gravitational force between two planetoids if each has a mass of 500,000,000kg and their centers of mass are 200km apart?

1-15A F = Gm 1 m 2 / r 2 F = 6.67x *500,000,000 2 / 200,000 2 F = 4.17x10 -4 N What is the gravitational force between two planetoids if each has a mass of 500,000,000kg and their centers of mass are 200km apart?

A2-15 If a 0.5 kg ball spins on a table at 12m/s, attached to a 1m string, what is the tension on the string?

4-20A2-15 If a 0.5 kg ball spins on a table at 12m/s, attached to a 1m string, what is the tension on the string? F = mv 2 / r F = 0.5*12 2 / 1 F = 72 N

A If a 5 kg bowling ball is spun vertically at 24m/s, attached to a 0.5m rope, what is the tension on the rope at the bottom of the circle?

Ft - Fg = mv 2 / r Ft = 5*24 2 /.5 +5*9.8 F = 5809 N FtFt FgFg

3-20 If one moon orbits a planet at a radius of 400,000 km, and has a period of 30 days, how long will it take a moon to orbit the planet at half the radius?

3-20A If one moon orbits a planet at a radius of 400,000 km, and has a period of 30 days, how long will it take a moon to orbit the planet at half the radius? R a 3 /T a 2 = R b 3 /T b 2 400,000 3 /30 2 = 200,000 3 /T b 2 T = 10.6 days

3-25 In a carnival ride which spins you in a vertical circle, how fast must it spin for you to feel weightless at the top if it has a radius of 2m?

3-25A In a carnival ride which spins you in a vertical circle, how fast must it spin for you to feel weightless at the top if it has a radius of 2m? Fg + Fn = mv 2 / r Fn = 0 mg = mv 2 / 2 Sqrt(2g) = v v = 4.43m/s

4-54-5A2-15 A baseball thrown horizontally from the pitcher’s mound travels 145 kph before hitting the ground 1.5 sec later. How far (in meters) is it from the mound to where the ball hits?

v x =145 km/hr (1000 m/km) (hr/3600 sec) = 40.3 m/sec  d x = v x t = (40.3 m)(1.5 sec) = 60.4 meters

A softball is tossed horizontally from a treehouse 4 meters tall, and the ball lands 20 meters from the treehouse. How fast was the ball thrown?

 d x = v x t and  d y = ( 1 / 2 )at 2  t = √(2  d y /a)  where  d y = 4 m t = √[2(4 m)/(10 m/s 2 ] = sec v =  d x / t = 20m / sec v = 22.4 m/s A softball is tossed horizontally from a treehouse 4 meters tall, and the ball lands 20 meters from the treehouse. How fast was the ball thrown?

A water balloon is launched up at 6.5 m/s and sideways at 4 m/s. How far (horizontally) does it travel before hitting the ground?

v fy = v iy + at,v fy = 0 m/s (top) ==> -v iy = at t = -v iy / a ==> t = (6.5 m/s) / (-10 m/s 2 ) = 0.65 sec time of flight = 2t = 1.3 sec  d x = v x t = (4 m/s)(1.3 sec) = 5.2 meters A water balloon is launched up at 6.5 m/s and sideways at 4 m/s. How far (horizontally) does it travel before hitting the ground?

If an object is launched upwards at 24 m/s and sideways at 12 m/s, how much time will it take before it reaches the top?

4-20A v f = v i + at (v f = 0 m/s) => t = -v f / a t = -(24 m/s) / (-10 m/s 2 ) = 2.4 sec If an object is launched upwards at 24 m/s and sideways at 12 m/s, how much time will it take before it reaches the top?

A water balloon is launched with a horizontal velocity of 10 m/s and a vertical velocity of 8 m/s. What is the balloon’s velocity at the top of its path?

10 m/s horizontally because the horizontal velocity of a projectile is constant A water balloon is launched with a horizontal velocity of 10 m/s and a vertical velocity of 8 m/s. What is the balloon’s velocity at the top of its path?

How can a pants pocket have something in it and still be empty?

It can have a hole in it. How can a pants pocket have something in it and still be empty?

You throw away the outside, then cook the inside, then eat the outside, then throw away the inside. What is it?

Corn on the cob.

5-15 Name the movie which gave us this quote: “Looks like you’ve been missing a lot of work lately” “I wouldn’t say I’ve been missing it, Bob.”

Name the movie which gave us this quote: “Looks like you’ve been missing a lot of work lately” “I wouldn’t say I’ve been missing it, Bob.” Office Space

5-20 What is the largest land carnivore in the world?

Polar Bear or Kodiak bear

5-25 What giant monster was once described as a cross between a Gorilla and a Whale, and in fact who’s name was a blend of these two words… (in another language)?

What giant monster was once described as a cross between a Gorilla and a Whale, and in fact who’s name was a blend of these two words… (in another language)? Godzilla Gorira & Kujari = Gojira