A small magnet of mass 1 g is levitated by a piece of superconductor. What is the force the magnet exerts on the superconductor? (g = 10m/s^2)
A woman stands on a bathroom scale in an elevator which is not moving. The scale reads 500 N. The elevator then moves downward at a constant velocity of 5 m/s. What does the scale read while the elevator descends with constant velocity?
A point source of sound on top of a police car emits a signal at 1000 Hz. If the car is traveling in a straight line at 20.0 m/s, what is the perceived wavelength (to three significant figures) as measured by someone standing on the road directly in front of the car? Take the speed of sound to be 335 m/s.
Converging lenses can produce:
only upright images
only inverted images
both upright and inverted images depending on the distance of the object
both upright and inverted images simultaneously
10 kg of the isotope tritium, which has a half-life of 12.3 years, is produced at a reactor. Which of the following values, in kg, is closest to the mass of tritium that will remain after 30 years?
A thin lens with focal length f is to be used as a magnifying glass. Which of the following statements regarding this situation is true?
A converging lens must be used, and the object be placed at a distance greater than 2 from the lens
A diverging lens must be used, and the object be placed between f and 2f from the lens
A converging lens must be used and the object be placed at a distance less than f from the lens
A diverging lens must be used and the object be placed at any point other than the focal point
In general. doubling the amplitude of a wave:
doubles the frequency
halves the period
quadruples the energy
doubles the speed
Ocean waves with a wavelength of 120 m approach the shore at the rate of 8 per minute. What is their speed (to two significant figures)?
Check all that are true for an ideal stationary fluid.
The density increases linearly with depth
Only the fluid at the surface is in mechanical equilibrium
The fluid below the surface has a propensity toward the mechanical equilibrium
The pressure increases linearly with depth
A woman floats comfortably in a sitting position in a body of water. Her entire torso (above the belly button) is above the surface of the water. What does this situation tell you about the water?
It's not possible
The water has a dissolve addictive (such as salt) which makes it much more dense than fresh water
The temperature of the water is significantly higher than normal
The woman is wearing a hat made of buoyant material
Four identical bulbs are connected in parallel to a 12V ideal battery. Two of them burn out. The remaining two:
Look brighter than before
Look the same as before
Look dimmer than before
A hockey puck struck by a hockey stick is given an initial speed of 10 m/s. If the coefficient of friction between the ice and the puck is 0.1, how far will the puck slide?
Ying and Albert are carrying Faisal on a horizontal stretcher. The stretcher is uniform, is 2.0 m long, and weighs 100N. Faisal weighs 800N. Faisal's centre of gravity is 75 cm from Ying. Ying and Albert are at the ends of the stretcher. The force that Albert is exerting to support the stretcher with Faisal on it is:
John and Hane are 10 m apart on an icy, frictionless lake. Jane's mass is 40 kg excluding the 1 kg ball she holds. John's mass is 59 kg. Jane throws the ball to John with a horizontal velocity of 10 m/s. How far apart are Jane and John 10 s later?