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.
Explanation:
It is given that,
The ramp is tilted upwards at 25 degrees and Paul is pulling a large crate up the ramp with a rope that angles 10° above the ramp.
Total angle with respect to ramp is 35 degrees.
If Paul pulls with a force of 550 N.
The horizontal component of the force is given by :



The vertical component of the force is given by :



Hence, this is the required solution.
Answer:
6840 N
Explanation:
The force acting on the car can be found by using Newton's second law:
F = ma
where
F is the net force on the car
m is the mass of the car
a is its acceleration
For the car in this problem,
m = 1800 kg

Substituting,

Answer:
The time constant is 1.049.
Explanation:
Given that,
Charge 
We need to calculate the time constant
Using expression for charging in a RC circuit
![q(t)=q_{0}[1-e^{-(\dfrac{t}{RC})}]](https://tex.z-dn.net/?f=q%28t%29%3Dq_%7B0%7D%5B1-e%5E%7B-%28%5Cdfrac%7Bt%7D%7BRC%7D%29%7D%5D)
Where,
= time constant
Put the value into the formula
![0.65q_{0}=q_{0}[1-e^{-(\dfrac{t}{RC})}]](https://tex.z-dn.net/?f=0.65q_%7B0%7D%3Dq_%7B0%7D%5B1-e%5E%7B-%28%5Cdfrac%7Bt%7D%7BRC%7D%29%7D%5D)





Hence, The time constant is 1.049.
Answer:
I) 420000J
ii)
Explanation:
(I) so you can use the formula for quantity of heat then substitute the values given
formula-Q=mc∆9