When did the extinction of the dinosaurs occur?
A) about 3.5 billion years ago
B) about 2 billion years ago
C) 540 million years ago
D) 65 million years ago
E) less than 1 million years ago
D
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Mercury's rotation and revolution are an example of a 3:2 resonance
Indicate whether the statement is true or false
A 0.38-kg block rests on a level surface and is attached to a horizontally aligned spring with a spring constant of 55.0 N/m. The block is initially displaced 4.8 cm from the equilibrium point and then released to set up a simple harmonic motion. A frictional force of 0.50 N exists between the block and surface. What is the speed of the block when it passes through the equilibrium point after
being released from the 4.8-cm displacement point? a. 0.21 m/s b. 0.32 m/s c. 0.64 m/s d. 0.46 m/s e. 1.8 m/s
A charged particle moving perpendicular to a magnetic field has a magnet force on it. But when an observer moves with the particle, so that the particle has a relative velocity of zero with respect to the observer, one would expect there would be no magnetic force. Yet there is still a force. If it is not a magnetic force, then what is the source of this force?
a. It is an electrical force. b. It is due to the ether. c. It is a gravitational force. d. It is something other than any of the above.
Briefly describe the Sun's 22 year activity cycle
What will be an ideal response?