From a point 96 ft above the ground, a stone is thrown in such a way that it is at the same point: 3 sec after it was thrown, as it was 2 sec after it was thrown. How long does it take the stone to reach the ground?

The minimum stopping distance for a car depends on the driver’s reaction time and the car’s acceleration when the brakes are applied. A 1000 kg car traveling on a level road at speed 18 m/s travels 15 m (due to driver’s reaction time) before braking starts and then skids with the wheels locked another 30 m. Answer the following questions concerning this stopping process. (Ignore air resistance and assume g = 10 m/s^2.)

a) What is the driver’s reaction time?

b)  How long did it take for the car to come to a complete stop: include both segments – the one when the car was still going at a constant speed, and the other one when the car brakes were applied?

c) Sketch a v(t) (I believe it is a velocity-time) graph for the car motion for the entire braking process of the car: from the moment the driver noticed danger to the moment the car completely stopped. Indicate relevant times and velocities on the graph.

d) Show that the magnitude of the net force acting on the car when the car was skidding was 5400 N.

I'm not sure how I should start this. If someone could explain and answer It would be great. (:

1. If 55.1 cm of copper wire (diameter = 1.18 mm, resistivity = 1.69 × 10^-8Ω·m) is formed into a circular loop and placed perpendicular to a uniform magnetic field that is increasing at the constant rate of 12.6 mT/s, at what rate is thermal energy generated in the loop?

2. A rectangular loop (area = 2.7 m²) turns in a uniform magnetic field, B = 3.2 T. When the angle between the field and the normal to the plane of the loop is π/2 rad and increasing at 2.6 rad/s, what emf is induced in the loop?

Using a rope that will snap if the tension in it exceeds 387 N, you need to lower a bundle of old roofing material weighing 449 N from a point 6.1 m above the ground. Obviously if you hang the bundle on the rope, it will snap. So, you allow the bundle to accelerate downward. (a) What magnitude of the bundle's acceleration will put the rope on the verge of snapping?

T-mg = -ma

Why are most of the solutions out there is just T-mg = ma?

Since acceleration down, is opposite direction of T, why is the equation to solve this is not T-mg = - ma ?

William Tell shoots an apple from his son's head. The speed of the 118-g arrow just before it strikes the apple is 20 m/s, and at the time of impact it is traveling horizontally. If the arrow sticks in the apple and the arrow/apple combination strikes the ground 7.7 m behind the son's feet, how massive was the apple? Assume the son is 1.85 m tall.

A sphere with radius a has uniform charge/volume.

A metal sphere shell has inner radius b(from center) and outer radius c(from center).

Between a and b is empty.

Outer metal shell has total charge Q₁

_{Please start with Gauss's law and show steps}

Find Electric field in region

a) r<a

b)a<r<b

c)b<r<c

d) r>c

An astronomical telescope is being used to examine a relatively close object that is only 107.00 m away from the objective of the telescope. The objective and eyepiece have focal lengths of 1.470 and 0.0900 m, respectively. Noting that the expression M = - f_o/f_e is no longer applicable because the object is so close, use the thin-lens and magnification equations to find the angular magnification of this telescope.

The drawing shows a skateboarder moving at 6.60 m/s along a horizontal section of a track that is slanted upward by θ = 52.0° above the horizontal at its end, which is 0.700 m above the ground. When she leaves the track, she follows the characteristic path of projectile motion. Ignoring friction and air resistance, find the maximum height H to which she rises above the end of the track.

We know why a charged rod can deflect water droplets which is because of the positive side of water molecule attracting to the negative side of the rod and vice versa. While explanation is true to some extent, it is not entirely. The question is : Can you figure out what is missing (what is another reason for its deflection besides the water molecule and rod's charges? Hint we have is: Water in the pipe is not only h20

An object 1cm tall is placed at 4cm from a convex lens with a focal length of 6cm. A convex mirror with a focal length of 4cm is situated 10cm from the convex lens. A)Using the thin lens equation calculate the location of the image. B)Describe the image using three of the following words; virtual, real , smaller, bigger, non-inverted, inverted.

YOUR HELP WILL BE APPRECIATED !!

Straight wooden rod of mass 6.0 kg, uniform cross-section 7 cm², and constant density 700 kg has a very small mass 0.8 kg attached to its one end. The rod is partially submerged in water of density 990kg/m³.  While in equilibrium, the rod floats in a vertical position with large part of it submerged. The rod is then pushed down by distance y_max from equilibrium and released resulting in its oscillation neat the surface of teh water.

(Assuming no drag forces are acting in this situation) and taking g to be 9.8 m/s²

A) Use the first principles to demonstrate that such system can be treated as Simple Harmonic Oscillator. ( Paper solution!!!)

B) Find the rod's period of oscillations to the nearest thousandth of a second.

( Enter this value into the answer box without units).

In addition to entering your final numerical answer into the box, make sure that you write your solution neatly starting with the clear diagram and all variables on it.

Solve this problem in detail on paper. Please annotate your solution -- make short comments/ arguments for steps you are making.

derive maxwell Boltzmann statistics law.

A force F⃗ of magnitude F making an angle θ with the x axis is applied to a particle located along axis of rotation A, at Cartesian coordinates (0,0) in the figure. The vector F⃗ lies in the xy plane, and the four axes of rotation A, B, C, and D all lie perpendicular to the xy plane. (Figure 1)

A particle is located at a vector position r⃗ with respect to an axis of rotation (thus r⃗ points from the axis to the point at which the particle is located). The magnitude of the torque τ about this axis due to a force F⃗ acting on the particle is given by

τ=rFsin(α)=(momentarm)⋅F=rF⊥ ,

where α is the angle between r⃗ and F⃗ , r is the magnitude of r⃗ , F is the magnitude of F⃗ , the component of r⃗ that is perpendicualr to F⃗ is the moment arm, and F⊥ is the component of the force that is perpendicular to r⃗ .

Sign convention: You will need to determine the sign by analyzing the direction of the rotation that the torque would tend to produce. Recall that negative torque about an axis corresponds to clockwise rotation.

In this problem, you must express the angle α in the above equation in terms of θ , ϕ , and/or π when entering your answers. Keep in mind that π=180degrees and (π/2)=90degrees

Part A

What is the torque τA about axis A due to the force F⃗ ?

Part B

What is the torque τB about axis B due to the force F⃗ ? (B is the point at Cartesian coordinates (0,b) , located a distance b from the origin along the y axis.)

Part C

What is the torque τC about axis C due to F⃗ ? (C is the point at Cartesian coordinates (c,0) , a distance c along the x axis.)

Part D

What is the torque τD about axis D due to F⃗ ? (D is the point located at a distance d from the origin and making an angle ϕ with the x axis.)

A 2.0 kg wood block is launched up a wooden ramp that is inclined at a 29 ∘ angle. The block's initial speed is 11 m/s . The coefficient of kinetic friction of wood on wood is μk=0.200.

What vertical height does the block reach above its starting point? What speed does it have when it slides back down to its starting point?