Homework Statement
A freezer has a coefficient of performance of 6.30. It is advertised as using electricity at a rate of 457kWh/yr.
a)On average how much energy does it use in a single day?
b) What maximum mass of water at 20.0 degree celsius could the freezer freeze in a single day...
Homework Statement
A square uniform raft, 18m by 18m of mass 6200kg is used as a ferry boat. if three cars each of mass 1350 kg occupy the NE, SE, and SW corners, determine the Centre of mass of the loaded ferryboat relative to the centre of the raft
Homework Equations
Center of mass...
Homework Statement
If the original height of a falling rock is y1 = h = 3.0m; calculate the rock's speed just before it hits ground.
Homework Equations
From conservation of mechanical energy law
1/2mv1^2 + mgy1 = 1/2mv2^2 + mgy2
The Attempt at a Solution
I think i'm supposed to find v2 i.e...
Homework Statement
A box of mass 6.0kg is accelerated from rest by a force across the floor at a rate of 2.0m/s for 7.0s. Find the net work done on the box.
Homework Equations
Work done = Force x distance
The Attempt at a Solution
F = ma
F = 6 x 2 = 12N
i solved for final...
Homework Statement
A ball is kicked in the air with an initial velocity of 15m/s at an angle of 37 degrees; 0.8 m above the ground. How long is the ball in the air????
Homework Equations
The Attempt at a Solution
I resolved the vector into its components and the y component was...
i think x would be zero right??? if dat's right what wuld y be??
Also ur notation is a bit confusing.. what is the vector A?? Also the vector in the positive y direction is supposed to be the resultant vector i.e B + C BUT u wrote B + A..i'm kinda confused there..
Homework Statement
A little assistance with this question:-
A vector, B, when added to the vector C = 3i + 4j yields a resultant vector which is in the positive y direction and has a magnitude equal to that of C. What is the magnitude of B?
Homework Equations
The Attempt at a...
Yeah, i know displacement is change in position... but am trying to find the distance first; because the question asks for both distance and displacement and i think we need to find the distance before we can get the displacement.. isn't that right???
Homework Statement
A car travels north at 30 m/s for one half hour. It then travels south at 40 m/s for 15
minutes. The total distance the car has traveled and its displacement are???
Homework Equations
The Attempt at a Solution
First of all i converted from m/s to km/h. I...
Hello, please any help will be very much appreciated;
A bullet is fired through a board, 14.0 cm thick, with its line of motion perpendicular to the face of the board. If it enters with a speed of 450 m/s and emerges with a speed of 220 m/s, what is the bullet's acceleration as it passes...