Answer:
Explanation:
Given that:
A circuit with a lagging 0.7 pf delivers 1500 watts and 2100VA
Here:
the initial power factor i.e cos θ₁ = 0.7 lag
θ₁ = cos⁻¹ (0.7)
θ₁ = 45.573°
Active power P = 1500 watts
Apparent power S = 2100 VA
What amount of vars must be added to bring the pf to 0.85
i.e the required power factor here is cos θ₂ = 0.85 lag
θ₂ = cos⁻¹ (0.85)
θ₂ = 31.788°
However; the initial reactive power 
= P×tanθ₁
the initial reactive power = 1500 × tan(45.573)
the initial reactive power = 1500 × 1.0202
the initial reactive power = 1530.3 vars
The amount of vars that must therefore be added to bring the pf to 0.85
can be calculated as:
The phase change (from gas to liquid) that the steam undergoes right when it touches your skin releases a lot of energy right onto your skin so it burns a ton. The boiling water would just burn you until it reaches the same temperature as your skin.
Answer:
The holiday lasted for 18 days.
Explanation:
Let's assume the number of days are as following:
let the rain in the morning and lovely afternoon = X days
Clear morning and rain in the afternoon = Y days
No rain in the morning and in the afternoon = Z days
Now according to the question
Number of days with rain = X + Y = 13 days
Number of days with clear mornings = Y + Z = 11 days
Number of days with clear afternoons = X + Z = 12 days
Solving above 3 equations, we get
X = 7, Y = 6 and Z = 5
Now total number of days on holiday = X+Y+Z = 7+6+5 =18
Hence, total number of days on holiday = 18 days.
If the runner is running in a circular track then yes when something or someone is moving in a circular motion at a constant speed they are indeed accelerating. They’re accelerating because the direction of the velocity vector is changing
Answer:
F= 2.86KN
Explanation:
The attached diagram shows the motion of crate on a single line The forces acting on it have been resolved as shown in the attached figure.The kinetic friction opposes the motion.Now crate is moving with constant speed so the acceleration is constant.
Applying Newton's second law to determine the force F and also substituting the values for 
to eliminate normal force
F = ma
Now 
and 
components are zero
Horizontal and vertical forces are Force on crate, weight of crate and kinetic friction
therefore 
>>> (1)
By putting the above equation in equation 1 we get F
By putting values we get
F = 
F= 2860.8 N
F= 2.86KN
