Physics v2
Pliz help with formulas to etisalaat.... urgent need))I would be grateful to all who even tries to solve it herself..in physics 0((((
1. The swimmer crosses the river, having a width h. At what angle A(alpha) to the direction of the current should not attempt to cross to the opposite Bank in the shortest time? Where is he in this case will be and what path's will float if the flow velocity is equal to u, and the velocity of the swimmer relative to the water is equal to v?
2. On an inclined plane forming an angle A(alpha) with the horizon, is a cube of mass m. The plane is in a lift moving with the acceleration a directed upwards. Find the force of pressure F of the cube on the plane. At what coefficient of friction k between the cube and the plane, the cube won't slip down?
Task №3. What force must be applied to the slab weighing 4 tons when lifting from the bottom of the reservoir, if the volume of the plate 2 m3 ?
The task №4. How many kilograms centigrade of steam required to heat the concrete slab weighing 200 kg from 10 to 40 0C?
The task №5. Determine the capacity of the electric kettle, if within 5 min it 1kg of water heated from 20 to 80 0C. Loss of energy negligible.
pliz help
Hhhhhhhh
No. 3
On the body there are three forces.
The force of gravity, downward, lifting force and buoyant force.
If teplica was in the air, the minimum lifting force would be equal in magnitude to the force of gravity.
In the water there is also a buoyant force pgV, where p is the fluid density, g is the gravitational acceleration, and V is the volume of the plate.
We write 2 z-n of Newton
F + F(A) + F(T) = 0
Projected on the axis directed upwards
F + pgV - mg = 0, where m is the mass of the plate.
We get F = g(m - pV) = 9.8(4000 - 1000*2) = 20000 N = 20 kN
No. 4
There is a heat balance equation, we write it
Q1 + Q2 = 0 where Q1 is the heat given to steam Q2 - heat received by the plate.
Because the heat given out is the sign of the equation will be written as
Q2 - Q1 = 0
Q1 = r*m1, where r is the latent heat of vaporization/condensation, and m1 is the mass of steam.
Q2 = c*m2(T2 - T1), where C is the specific heat of concrete, m2 - the mass of concrete, T1,T2, respectively the starting and ending temperature of the plate.
Easily find m1
m1 = c*m2(T2 - T1)/r alas don't remember the heat capacity of the concrete and the specific heat of vaporization of water, but it is in tables, you can see.
No. 5
The electric current in the kettle does work with time t equal to N*t, where N is the power.
This work is used for the heating of water of mass m.
Thus:
A = Q
N*t = cm(T2-T1), where N = cm(T2-T1)/t = 4200*1*(80-20)/300 = 4200*60/300 = 840 W
MissKissGalina
You have the task-interesting, but alas, I can't unsubscribe because in a hurry. Here is the uncomfortable message sheet.
at the moment, will be able to tell that in the first task
the minimum time for which the catcher with velocity v will cross the river anyway
tmin = h/v, but it is in stagnant water.
Given the speed of the river it is necessary that the swimmer has reached the other shore at the same time, but sailing at an angle to the perpendicular to the river. Respectively for the minimum time necessary to the component of resultant velocity perpendicular to the shore, was equal to v.
Thus V*cosA = v, V = Sqrt(v^2 + u^2) so Cos A = v/Sqrt(v^2 + u^2).
Define the path that the swimmer swims
S = V*tmin = Sqrt(v^2 + u^2)*h/v
The position of the swimmer relative to the shore, nekotoruyu he would swim in still water is equal to
L = Sqrt(S^2 - h^2) = h*Sqrt((v^2 + u^2)*/v^2 - 1)
Vautour solved in non-inertial reference frame. Alas longer to write than to solve. Will come back and finish it.
Please tell me.
How will the change in angular velocity of rotating around its own axis platform, If the goods are standing in the center of it will move closer to the boundaries of the platform? And why would she change so much?
FON-Dorn
The angular velocity of platform motion Pestana [rad/s], linear speed load [km/h] will change when you move from the center to the edge of the disk. There simple, formula get myself.
Shkolota, when it was, nostalgia )...
PS Take a book Goldfarb and progresi all sections. Get a sea fan (they're interesting).
help me please to solve 3 tasks:
1. The speed with which uniformly roll a cart with a mass of 500 g when the momentum is 5 kg*m/s ?
2. Two balls of masses 2 and 8 kg are moving towards each other with velocities 10 m/s and 2 m/s, respectively. The speed with which they will proceed when it is completely inelastic impact?
3.With a stationary boat, the weight of which together with a man equal to 255 kg, is thrown on shore paddle weighing 5 kg with a horizontal velocity relative to the earth is 10 m/s. What speed gets the boat?
1. The challenge for the formula for momentum: p=mv where p is momentum [kg*m/c], m-mass of body[kg], V is the velocity of the body[m/c] . A lot 500грамм must be in SI (in kgs) and it is 500 divided by 1000, i.e. 0.5 kg. it is necessary to Express the velocity: V=p/m = 5/0,5 = 10 m/s
2. The challenge for the law of conservation of momentum: the initial momentum equal to final momentum. m1v1+m2v2=m1vк+m2vk , where m1 and m2 - masses of 1 and 2 balls respectively, v1 and v2 - speed of the balls before impact, vk - final speed of the balls (after the inelastic impact, the balls stick together and move as a single unit). Express the final speed vk(m1+m2)=m1v1+m2v2 ; vk=(m1v1+m2v2) / (m1+m2) = (2*10 + 8*2) / (2+8) = 36/10 = 3,6 m/c
3. The same law. Only design it on the x-axis. The initial momentum of the system is 0 since nothing is moving. The final momentum: muesli*Vвесла - lodki*Vлодки (minus sign, because the speed with which they have different directions: the boat in one direction sailed, and paddle thrown in the opposite direction (this is, in fact, the reason of the movement of the boat) ) . Equate pulses: 0=muesli*Vвесла - lodki*Vлодки . Express Vлодки : Vлодки=muesli*Vвесла/lodki = 5*10/255=0.20 m/c
The exam in physics not pass?
how to calculate the vector, and the force of gravity for the wrong body
for example for a cube?
it is assumed that the closer to the top of gravity will become stronger and change the angle of the gravitational acceleration.
Good people who know ka to solve ?
after hitting the hockey puck on its initial speed is vo. the puck slides across the horizontal surface of the ice, and after 3 s the velocity is 14m/s. the coefficient of sliding friction of the puck on the ice is 0.15.determine the value of v0
ALKATRAZ_XXL
acceleration (i.e. braking, it is constantly since the sum of the forces applied to the puck in time does not change):
a=(V-Vo)/t=(13-Vo)/3
This figure needs to be done. Then the 2 Newton's law to record projections:
-on axis x (directed horizontally to the right): (sign of the acceleration is already included in the formula of acceleration)
m*a=-Fтр
on the y-axis: N-m*g=0 (3-Newton's law - 2 bodies act on each other with forces equal to each other and oppositely directed along the same straight line) where N=m*g. In the task body slip, then the friction force Fтр=f*N=f*m*g , where f is the friction coefficient (0,15). Substitute in the projection on the x axis:
m*a=f*m*g . Abbreviated m. a= -f*g. We substitute the acceleration (13-Vo)/3=-f*g . Express 13-Vо=-f*g*3 , then Vo=13+f*g*3= 13+0,15*9.8*3= 17,41 m/s . All, the problem was solved.
Dave Castaraider aka looten duke
Thank you very much. There had been speculation about mg, as well as finding the acceleration, but to tie all these things. Also knew what must be considered the bearing area. And also I know that the picture are also needed. But the solution to the difficulty caused. Thanks again.
please help 1. a ball of mass 1kg radius 30cm hanging from a smooth vertical wall on a rope with a length of 1 m. Determine the tension force of the rope and the pressure force of the ball on the wall. Friction of the cord against the wall neglected
2. Material point performs harmonic oscillations with amplitude A=8 cm and period T=4S . Determine how the equation changes the coordinates of the point if the offset point moment time adopted by the primary, is zero.
If all of these formulas in physics, just not to push the head of his daughter, which method it is possible to do, anyone have any options?