Master Physics with Fun Quizzes & Brain Teasers!

Two spaceships approach the Earth from opposite directions. According to an observer on the Earth, ship A is moving at a speed of 0.687c and ship B at a speed of 0.863c. What is the velocity of ship Aas observed from ship B? Of ship B as observed from ship A? (Indicate the direction with the sign of your answer. Assume ship A is moving in the positive direction).ship A observed from ship B ____cship B observed from ship A ____c
1 Answer
the red laser is turned off, and the green laser is turned on. what happens to the central maximum?
1 Answer
fill in the blank. A moving cue ball strikes another ball of equal mass that is initially at rest. If the collision is elastic, the velocity of the cue ball after the collision will be __________ to the velocity of the other ball.
1 Answer
how to find the angle of inclination of a multivariable function
1 Answer
a spinning top completes 6.0010^3 rotations before it starts to topple over. the average angular speed of the rotations is 8.0010^2 rpm. calculate how long the top spins before it begins to topple.
1 Answer
what is wsafe , the largest weight of the load that is safe to lift regardless of the angle of the crane's arm?express wsafe in terms of w , c , and b .
1 Answer
the w8 x 67 wide-flange a-36 steel column can be assumed fixed at its base and pinned at its top. determine the largest axial force p that can be applied without causing it to buckle.
1 Answer
an airplane flies at 550 km=hr at 1500 m altitude on a standard day. the plane climbs to 15,000 m and flies at 1200 km=h. calculate the mach number of flight in both cases.
1 Answer
at what angle will 614 nm light produce a first-order maximum when falling on a grating whose slits are 1.43 10-3 cm apart?
1 Answer
In the three-phase circuit with a positive sequence, the instantancous voltage and current for phase a are givenas Va (t) = Umsin(ct) and iq (t) = imsin(wt - 0), respectively.(a) Derive expressions for instantaneous power Pa (t), P. (t) and pe(t).(b) Derive an expression for three-phase instantaneous power Pa (t) + P. (t) + P. (C).
1 Answer
if the fundamental vibrational frequency for the ethylene double bond is 2000 cm-1 , what is the wavelength in nm for the first harmonic vibration frequency
1 Answer
a proton is located at x = 1.0 nm, y = 0.0 nm and an electron is located at x = 0.0 nm, y = 4.0 nm. find the attractive coulomb force between them. (the value of k is 9.0 109 nm2/c2.)
1 Answer
manhattan distance is the distance traveled as if traveled along rectangular city blocks. the manhattan distance for the standardized observations of (1.85, 0.65) and (0.55, 0.75) is _____.
1 Answer
A block of wood is floating in a pool of water. (a) Is the buoyant force acting on the block greater than, less than, or equal to the weight of the block? Explain. (b) Is the volume of the fluid displaced by the block greater than, less than, or equal to the volume of the block? Explain.
1 Answer
A powerful bolt of lightning can carry a current of 230 kA. part a) Treating a lightning bolt as a long, thin wire, calculate the magnitude of the magnetic field produced by such a bolt of lightning at a distance of 33m . part b) If two such bolts strike simultaneously at a distance of 33m from each other, what is the magnetic force per meter exerted by one bolt on the other?
1 Answer
a 4 kg ball swings in a vertical circle on the end of an 60-cm-long string. the tension in the string is 20 n when its angle from the highest point on the circle is =30A What is the ball's speed when =30? Express your answer to two significant figures and include the appropriate unitsWhat is the magnitude of the ball's acceleration when =30? Express your answer to two significant figures and include the appropriate unitsWhat is the direction of the ball's acceleration when =30? Give the direction as an angle from the r-axis Express your answer to two significant figures and include the appropriate units.
1 Answer
A 3.20-mm-tall object is 20.0 cm from the vertex of a spherical mirror. The mirror forms an image 60.0 cm from the mirror. If the image is real, what is the radius of curvature of the mirror? What is the height of the image? Is it upright or inverted?
1 Answer
Block 1 is resting on the floor with block 2 at rest on top of it. Block 3, at rest on a smooth table with negligible friction, is attached to block 2 by a string that passes over a pulley, as shown above. The string and pulley have negligible mass. (a) i. On the dot that represents block 1, draw and label the forces (not components) exerted on block 1. Each force must be represented by a distinct arrow starting on, and pointing away from the dot. Draw the relative lengths of all arrows to reflect the relative magnitudes of the forces. ii. On the dot that represents block 2, draw and label the forces (not components) exerted on block 2. Each force must be represented by a distinct arrow starting on, and pointing away from the dot. Draw the relative lengths of all arrows to reflect the relative magnitudes of the forces. (d) On the axes below, sketch graphs of the velocity and the acceleration of block 2 after block 1 has been removed.
1 Answer
a 550-turn solenoid is 13 cm long. the current into it is 34 a . a 3.7 cm -long straight wire cuts through the center of the solenoid, along a diameter. this wire carries a 28 a current downward (and is connected by other wires that don't concern us).
1 Answer
for the bending design of a prismatic beam, usually the required beam's section modulus is determined first. which of the following is the correct expression of the section modulus in terms of the maximum bending moment and allowable bending stress of the beam?
1 Answer
A 50 cm long center-fed dipole directed along the z direction and located at the origin is excited by a 1 MHz source. If the current amplitude is 10 = 20 A, determine the power density radiated at 2 km along the broadside of the antenna pattern.
1 Answer
consider microwaves which are incident perpendicular to a metal plate which has a 1.8-cm slit in it. part a determine the wavelengths for which diffraction minima are observed. check all that apply. determine the wavelengths for which diffraction minima are observed.check all that apply. 3 cm 0.5 cm 1 cm 4 cm
1 Answer
it takes 40 j to push a large crate 4 m across a floor. the force exerted on the crate is A. 160 nB. 4 nC. 40 nD.. 10 nE. 1600 n.
1 Answer
a capacitor is connected to an ac source. if the maximum current in the circuit is 0.400 a and the voltage from the ac source is given by v = (89.2 v) sin[(82)s1t], determine the following. (a)the rms voltage (in V) of the source V, (b)the frequency (in Hz) of the source Hz, (c)the capacitance (in F) of the capacitor F
1 Answer