A sixth grader moves down the hall at 1.2 m/s. When he sees a bunch of eighth graders coming, he

A child of mass 40.0 kg is in a roller coaster car that travels in a loop of radius 7.00 m. at point a the speed of the car is 1

pav-90 [236]

I attached the missing picture.
The force of seat acting on the child is a reaction the force of child pressing down on the seat. This is the third Newton's law. The force of a child pressing down the seat and the force of the seat pushing up on the child are the same.
There two forces acting on the child. The first one is the gravitational force and the second one is centrifugal force. In this example, the force of gravity is always pulling down, but centrifugal force always acts away from the center of circular motion.
Part A
For point A we have:
$F_a=F_cf-F_g$
In this case, the forces are aligned, centrifugal is pointing up and gravitational is pulling down.
$F_a=m\frac{v^2}{r}-mg=179 $N$
Part B
At the point, B situation is a bit more complicated. In this case force of gravity and centrifugal force are not aligned. We have to look at y components of this forces, y-axis, in this case, is just pointing upward.
$F=F_{cf}\cos(30)-mg=m\frac{v^2}{r}\cos(30)-mg=153.2$N$
Part C
The child will stay in place at point A when centrifugal force and force of gravity are in balance:
$F_g=F_{cf}\\
mg=m\frac{v^2}{r}\\
gr=v^2\\
v=\sqrt{gr}=8.29\frac{m}{s}$

6 0

2 years ago

ASK YOUR TEACHER A baseball with a mass of 146 g is thrown horizontally with a speed of 40.6 m/s (91 mi/h) at a bat. The ball is

RideAnS [48]

Answer:

Explanation:

mass of the ball = 146 g = 146 / 1000 = 0.146 kg

initial speed of the ball = 40.6 m/s

final speed of the ball = - 45.1 m/s

time of impact = 1.05 ms = 1.05 / 1000 = 0.00105 s

impulse, Ft = change in momentum = mv - mu = m (v-u)

F = m (v - u) / t = 0.146 kg ( -45.1 -40.6) / 0.00105 s = -11916.4 N

4 0

2 years ago

Consider a single photon with a wavelength of lambda, a frequency of nu, and an energy of E. What is the wavelength, frequency,

BARSIC [14]

Answer: lambda $\lambda$ , nu $\nu$ , and 100E

Explanation:

The energy $E$ of a photon is given by:

$E=h\nu$ (1)

Where:

$h$ is the Planck constant

$nu$ is the frequency

On the other hand, we have an expression that relates the frequency of the photn with its wavelength $\lambda$ :

$nu=\frac{c}{\lambda}$ (2) where $c$ is the speed of light

Substituting (2) in (1):

$E=h\frac{c}{\lambda}$ (3) This is the energy for a single photon

For 100 photons, the energy is:

$100E=100(h\frac{c}{\lambda})=100h\nu$ (3)

Where the wavelength and the frequency of the light remains constant.

Therefore, the answer is:

$\lambda$ , $\nu$ , and 100E

5 0

2 years ago

Select all that apply. Select the items that describe an economy at equilibrium.

ella [17]

The correct answers are:

B) Producers supply enough goods for consumers;

D) Supply equals demand;

In the economics, the equilibrium state basically means that the supply in the market is well balanced with the demand on the market, thus leading to an ideal economic state within the economy. The equilibrium will essentially mean that the supply is equal to the demand, thus there will be maximum efficiency. Also, since the producers are managing to supply just the right amount of goods to the consumers, everyone will benefit, with the consumers always have what they want, and the producers always have all of their products sold.

8 0

3 years ago

An optical disk drive in a computer can spin a disk at up to 10,000 rpm. If a particular disk is spun at 5050 rpm while it is be

Ber [7]

Answer:

α = 1215.71 rad/s²

Explanation:

The angular acceleration of an object is defined as the time rate of change of angular velocity of he object. The formula for the angular acceleration of an object is given as follows:

α = (ωf - ωi)/Δt

where,

α = angular acceleration of the disk = ?

ωf = Final Angular Velocity = 0 rad/s (Since disk finally stops)

ωi = Initial Angular Velocity = (5050 rpm)(2π rad/rev)(1 min/60 s)

ωi = 528.83 rad/s

Δt = time interval = 0.435 s

Therefore,

α = (0 rad/s - 528.83 rad/s)/(0.435 s)

α = - 1215.71 rad/s²

here, negative sign indicates that the direction of acceleration is opposite to the direction of angular velocity or the angular motion. So, the magnitude of acceleration will be:

4 0

2 years ago