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A diver of mass 60 Kg dives from a height of 10 m into a swimming pool. Through the air there is resistance of 50 N a) Find the speed at which the diver enter the water b) Once in the water, the water provides an upward force of 2000 N. Find the greatest depth in water the diver reaches.
A positive point charge q1 at the origin and a negative charge q2 at x=2m. The resultant electric field is 10.8 i N/C at x=1m and -8 i N/C at x=3m. Find q1 and q2.
One CD player is said to have a signal-to-noise ratio of 84 dB
dB, whereas for a second CD player it is 95 dB
dB. What is the ratio of intensities of the signal and the background noise for the first device?
Express your answer using two significant figures.
A crate at rest with a mass of 75 kg is being pushed by a force of 620 N. If the coefficient of kinetic friction between the crate and the floor is 0.55, determine how fast the crate will accelerate, and how far the crate will travel in 3.0 seconds.
An electron penetrates the region between two uniformly charged horizontal plates, but oppositely signed. Its initial speed, at half distance between the plates is 2×10 ^6 i m/s. The plates have a length of 4 cm and are 1.6 cm apart. In the whole region between the plates, the electric field ́ is uniform and perpendicular to the plates. (a) what is the maximum modulus that the vertical electric field can have so that the electron does not touch any plate?
The answer is 228 N/C but I'm not too sure how they got that?
The density of gold is 19.3 g/ cm3. What is this value in kilograms per cubic meter?
The nucleus of a plutonium-239 atom contains 94 protons. Assume that the nucleus is a sphere with radius 6.64 fm and with the charge of the protons uniformly spread through the sphere. At the surface of the nucleus, what are the (a) magnitude and (b) direction (radially inward or outward) of the electric field produced by the protons?
1. How long will a bus take to travel 150 km at an average speed of
40 km/h?
2.
2. A cheetah can run at 30 m/s, but only for about 12 s. How far
will it run in that time?
3. It takes a cheetah just 3 s to reach its top speed of 30 m/s.
What is its acceleration?
What is the energy exchange that occurs when a clock spring unwinds?
- A pendulum has 15J of potential energy at the top of its swing.
a) What is its kinetic energy at the bottom of its swing?
