A ball is thrown upward from the ground. You observe the ball through a window on its way up, and notice it was visible for 2 seconds while it travels from the bottom of the window to the top, which is a length of 43.42 metres. a) How much time does it take for the ball to be seen again (in seconds)? b) How far above top of window will the ball reach (in metres)? |

In: Physics

A sheet of charge with ρS = 8 nC/m2

is in the plane x = 5 in free space and a line

charge ρL = 15 nC/m is located at x = 2, z = 5.

a. Find E at P(0, 0, 0)

b. E at (4, 5, 6)

c. What is the force per unit length on the line charge?

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6.
A person holds a rifle horizontally and fires at a target. The
bullet has a muzzle speed of 150 m/s, and the person hears the
bullet strike the target 0.80 s after firing it. The air
temperature is 71°F. What is the distance to the target?

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A soccer player takes a corner kick, lofting a stationary ball
36.0° above the horizon at 16.0 m/s. If the soccer ball has a mass
of 0.425 kg and the player's foot is in contact with it for 4.80 ✕
10^{−2} s, find the *x*- and *y*-components
of the soccer ball's change in momentum and the magnitude of the
average force exerted by the player's foot on the ball.

(a)

the *x*- and *y*-components of the soccer ball's
change in momentum (in kg · m/s)

Δ*p*_{x}

= kg · m/s

Δ*p*_{y}

= kg · m/s

(b)

the magnitude of the average force exerted by the player's foot on the ball (in N)

N

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You have been hired as a technical consultant for an early-morning cartoon series for children to amke sure that the science is correct. In the script, a wagon containing two boxes of gold (total mass of 150kg) has been cut loose from the horses by an outlaw. The wagon starts from rest 50 meters up a hill with a 6 degree slope. The outlaw plans to have the wagon roll down the hill and across the level fround and then crash into a canyon where his confederates wait. But in a tree 40 meters from the edge of the canyon wait the lone ranger (mass 80kg) and Tonto (mass 70kg). They drop vertically into the wagon as it passes beneath them. The script states that it takes the lone ranger and tonto 5 seconds to grab the gold and jump out of the wagon, but is this correct? You assume that the wagon rolls with negligeble friciton.

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A block with a mass of m = 33 kg rests on a frictionless surface and is subject to two forces acting on it. The first force is directed in the negative x-direction with a magnitude of F1 = 11.5 N. The second has a magnitude of F2 = 23 N and acts on the body at an angle θ = 22° measured from horizontal, as shown. write an expression for the component of net force, Fnet,x, in the x direction, in terms of the variables giving in the problem statement. write an expression for the magnitube of the normal force, Fn, acting on the block, F2 and the other variables of the problem. Assume that the surface it rests on it rigid. Find the block's acceleration in the x-direction, ax, in meters per second squared

In: Physics

How is the direction of torque perpendicular to the plane of rotation (according to the cross product of F and r)? It seems very counterintuitive and doesn't seem to make sense.

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Consider the following:

If two equal mass objects had the same change in kinetic energy
during an interval, then they were acted on by the same net force
for that interval.

(a) Is this statement valid? __________

(b) If you contend the statement is valid, how do you know?

(c) If you contend the statement is invalid, what is wrong with
it?

(d) If the statement is invalid, restate it to give a valid
statement.

(e) Is the valid statement (original, or your revision) a
conditional or a bi-conditional? How do you know?

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Water molecules have a dipole moment of 6.2 x 10-30 C-m because oxygen is more electronegative than hydrogen. If a water molecule sits at the origin and an electron sits at x= 10 nm, what is the magnitude of the force on the electron in fN? "f" is for femto b. In which direction is the force on the electron at x = 10 nm? c. What is the force on an electron that sits at y = 10 nm in fN? d. In which direction is the force on the electron at y = 10 nm?

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In
a football match, a player takes a free kick against the opponent's
team's goal. The ball is placed at 25. 0 m in front of one of the
goal posts and the player kicks the ball at an angle of 60. 0 °
with respect to the horizontal grass. If the goal has a height of
2. 3m, what speed should the ball print to make the goal from all
the angle of the goal?

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A ball is dropped from a building of height 100m. At the same
time, another ball is then thrown vertically up from the ground
with a velocity V_{0. }They meet each other at
the middle. What is the speed V_{0} of the ball thrown
vertically up?

a) 44.3m/s

b)9.8m/s

c) 31.3m/s

d)19.6 m/s

e) 98.0m/s

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PLEASE DO 1 AND 2. Thank you !!

1. A test charge of +2.5 μC is placed halfway between a charge
of +6 μC and another of +4 μC separated by 13.4 cm. What is the
magnitude of the net force on the test charge?

2. Common transparent tape becomes charged when pulled from a
dispenser. If one piece is placed above another, the repulsive
force can be great enough to support the top piece's weight.
Assuming equal point charges (only an approximation), calculate the
magnitude of the charge if electrostatic force is great enough to
support the weight of a 5.52 milligrams piece of tape held 2.11 cm
above another.

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*explain in 1 paragragh each*

1. Explain(1 paragragh) why plate area is directly related to
capacitance, plate charge, and energy.

2. Explain(1 paragragh) why seperation distance is inversely
related to capacitance, plate charge and stored energy.

3. Explain(1 paragragh) why each dielectric is different from
the rest.

4. What general mathematic word or phrase best describes the
differences?

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A charge of 3.06 is held fixed at the origin. A second charge of 3.06 is released from rest at the position (1.11 m, 0.524 m). If the mass of the second charge is 2.73 g, what is its speed when it moves infinitely far from the origin? At what distance from the origin does the 3.06 charge attain half the speed it will have at infinity?

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A
boy in a tree throws an apple upward with a speed of 8 m/s, how
long does the apple take to reach the ground , 5m below the boy?
How fast is the apple moving just before it strikes the
ground?

In: Physics