Answer:
a)15 N
b)12.6 N
Explanation:
Given that
Weight of block (wt)= 21 N
μs = 0.80 and μk = 0.60
We know that
Maximum value of static friction given as
Frs = μs m g = μs .wt
by putting the values
Frs= 0.8 x 21 = 16.8 N
Value of kinetic friction
Frk= μk m g = μk .wt
By putting the values
Frk= 0.6 x 21 = 12.6 N
a)
When T = 15 N
Static friction Frs= 16.8 N
Here the value of static friction is more than tension T .It means that block will not move and the value of friction force will be equal to the tension force.
Friction force = 15 N
b)
When T= 35 N
Here value of tension force is more than maximum value of static friction that is why block will move .We know that when body is in motion then kinetic friction will act on the body.so the value of friction force in this case will be 12.6 N
Friction force = 12.6 N
<h3><u>Given</u> :</h3>
Three identical resistors of resistances 5Ω, 10Ω and 30Ω are connected with a battery of 12V
<h3><u>To Find</u> :</h3>
We have to find current through the each resistor and equivalent resistance of circuit
<h3><u>SoluTion</u> :</h3>
➝ Equivalent resistance of series connection is given by
➝ We know that, Equal current flow through each resistor in series connection.
➝ As per ohm's law, Current flow through a conductor is directly proportional to the applied potential difference.
◈ <u>Equivalent resistance</u> :
⇒ Req = R1 + R2 + R3
⇒ Req = 5 + 10 + 30
⇒ <u>Req = 45Ω</u>
◈ <u>Current flow in circuit</u> :
⇒ V = IReq
⇒ 12 = I × 45
⇒ <u>I = 0.27A</u>
፨ Therefore, 0.27A current will flow through each resistor.
Answer:
a) A=0.125 m
b) T = 1.72 s
c) f= 0.58 Hz
Explanation:
a) As we are told that the maximum displacement from the equilibrium position was 0.125 m (from which it was released at zero initial speed), this is the amplitude of the resultant SHM, so, A=0.125 m
b) In order to find the period, we must get the total time needed to complete a full cycle (which means that the block must pass twice through the equilibrium point). We are told that at t=0.860 sec, the block has reached to the other end of the trajectory, and it has passed through the equilibrium point only once.
This means that the period must be exactly the double of this time:
T = 2*0. 860 sec = 1.72 sec.
c) In a SHM, the frequency is defined just as the inverse of the period (like in a uniform circular movement), so we can get the frequency f as follows:
f = 1/T = 1/ 1.72 s= 0.58 Hz
Answer:
112.58
Explanation:
The Coefficient of Performance of any system is denoted by COP=Q/W, where Q is the useful heat supplied or removed and W is the work required by the system. According to the first law of thermoddynamics Qh= Qc + W, where Qh is the heat transfered to the hot reservoir and Qc is the heat collected from the cold reservoir. Substituting the values for W and apllying the limitation for maximum theoretical efficiency we end up with the eqution shown below.
The Coefficient of Performance of air conditioner or COP is denoted by
COP(cool) = Tc/(Th- Tc)
where Tc: the lowest temperature
Th: the highest temperature
converting the values to Kelvin and adding them in the above equation
COP(cool) = (25+273)/((34+273)-(25+273))
= 298/(307-298)
= 298/9 = 33.11
From the question, it is stated that COP=SEER/3.4
hence, SEER= COP * 3.4
SEER= 33.11 * 3.4 = 112.58
Answer:
1) improve the quality of data
2) new system is more simple and elegant
Explanation:
the reason for being selected new system of determining planetary positions are
1) he want to improve the quality of data for having new planetary positioned value.
b) he believed that new system is more simple and elegant for determining planetary positions by both skilled and unskilled user i.e. astronomers and general public
