Answer:
Work done, W = 6153.31 Joules
Explanation:
It is given that,
Weight of piano, W = F = 7382 N
It is pushed 2.16 meters friction less plank
The angle with horizontal, 
When the piano slide up plank at a slow constant rate. The y component of force is taken into consideration. The net force acting on it is given by :
Work done is given by :
W = 6153.31 Joules
So, the work done in sliding the piano up the plank is 6153.31 Joules. Hence, this is the required solution.
Answer:
No, the sound produced by screeching brakes is not a useful form of energy, because it does not contribute to stopping the car.
The directions of the vectors for velocity and acceleration are in the opposite directions.
- The velocity vector is always in the direction of motion of the object. So, the direction of velocity is in the right from our point of view.
- When there is a positive acceleration in the object the acceleration vector is in the direction of motion of the object. When there is a negative acceleration in the object the acceleration vector is in the opposite direction of motion of the object. So, the direction of velocity is in the left from our point of view.
Velocity vector is the rate of change of position of an object. Acceleration vector is the rate of change of velocity of an object.
Therefore, the directions of the vectors for velocity and acceleration are in the opposite directions.
To know more about velocity and acceleration vectors
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<span>The factors that determine how fast weathering occurs are the type of rock, type of soil, time it takes, and the climate.</span>
Answer: a) 7.1 * 10^3 N; b) -880 N directed out of the curve.
Explanation: In order to solve this problem we have to use the Newton laws, then we have the following:
Pcos 15°-N=0
Psin15°-f= m*ac
from the first we obtain N, the normal force
N=750Kg*9.8* cos (15°)= 7.1 *10^3 N
Then to calculate the frictional force (f) we can use the second equation
f=P sin (15°) -m*ac where ac is the centripetal acceletarion which is equal to v^2/r
f= 750 *9.8 sin(15°)-750*(85*1000/3600)^2/150= -880 N
