Collisions
A 300g bird flying at 6 m/s sees a 10g insect coming straight towards it at 30 m/s. The bird opens its mouth and enjoys lunch.
This is the bird's speed immediately after swallowing.
What is 4.8 m/s?
A 5000 kg open train car is rolling on frictionless rails at 22 m/s when it starts pouring rain. A few minutes later, the car's speed is 20 m/s.
This is the mass of water that has collected in the car.
What is 500 kg?
A 20 kg child is on a swing that hangs from 3.0 meter long chains.
This is her maximum speed if she swings out to a 45° angle.
What is 4.2 m/s?
A skater holds her arms outstretched as she spins at 180 rpm.
This is the speed of her hands if they are 140 cm apart.
What is 13.2 m/s?
This modern country encompasses the ancient region of Mesopotamia.
What is Iraq?
A 20 g ball of clay traveling east at 3.0 m/s collides with a 30 g ball of clay traveling north at 2.0 m/s.
These are the speed and direction of the resulting ball.
What is 45 north of east (or east of north) at 1.7 m/s?
A sled slides along a horizontal surface on which the coefficient of kinetic friction is 0.25. It's velocity at point A is 8.0 m/s and at a later point B is 5.0 m/s.
This is the time it takes for the sled to travel from A to B.
What is 1.2 seconds?
A drum major twirls a 96 cm long, 400 g baton about its center of mass at 100 rpm.
This is the baton's rotational kinetic energy.
What is 1.68 J?
A 100 g ball and a 200 g ball are connected by a 30 cm long massless, rigid rod. The balls rotate about their center of mass at 120 rpm.
This is the speed of the 100g ball.
What is 2.5 m/s?
American Ballet Theatre's first African American prima ballerina.
Who is Misty Copeland?
Ball 1, with a mass of 100 g and traveling at 10 m/s, collides head on with ball 2, which has a mass of 300 g and is initially at rest.
These are the final velocities of both balls if the collision is perfectly elastic or perfectly inelastic.
What are -5 m/s and 5 m/s, and what is 2.5 m/s?
Squids use jet propulsion to move around. A 1.5 kg squid drifting at 0.40 m/s suddenly expels 0.10 kg of water backward to get itself moving forward at 2.5 m/s.
Ignoring drag, this is the speed relative to itself that the squid ejects water.
What is 32 m/s ?
A particle has potential energy modeled by:
U(x) = x + sin(2x) over the range 0 <= x <= π meters.
These are the equilibrium positions of the particle.
What are π/3 and 2π/3 ?
A 25 kg solid door is 220 cm tall and 91 cm wide.
This is the door's moment of inertia for a rotation on its hinges.
What is 6.9 kg*m2 ?
The school of philosophy that Marcus Aurelius belonged to.
What is Stoicism?
A 20 g ball is fired horizontally with speed v0 toward a 100 g ball hanging motionless from a 1.0 m long string. The balls undergo a head on, perfectly elastic collision, after which the 100 g ball swings out to a maximum angle of 50°.
This is v0.
What is 7.9 m/s?
A spaceship of mass 2.0*106 kg is causing at a speed of 5.0*106 m/s, when the antimatter reactor fails, blowing the ship into 3 pieces. The first section of mass 5.0*105 kg, is blown straight back with a speed of 2.0*106 m/s. The second piece of mass 8.0*105 kg, continues forward at 1.0*106 m/s.
These are the speed and direction of the third piece of spaceship.
What is 1.5*107 m/s, forward?
A massless tray hangs from a spring that is suspended from the ceiling. When empty, the pan is 50 cm below the ceiling. If a 100 g clay ball is placed gently on the pan, the pan hangs 60 cm below then ceiling. Suppose the clay ball is dropped from the ceiling onto the empty tray.
This is the tray's distance from the ceiling when the spring reaches its maximum length.
What is 93 cm?
Starting from rest, a 12 cm diameter CD takes 3.0 seconds to reach its operating angular velocity fo 2000 rpm. Assume that the angular acceleration is constant. The disk's moment of inertia is 2.5*10-5 kg*m2.
This is the torque applied to the disk and the number of revolutions it makes before reaching full speed.
What are 1.75*10-3 N*m and 50 revolutions?
The founder of Pakistan.
Mohammed Ali Jinnah.