Explanation:
Q1) What is the speed of the tip of the minute hand of a clock where the hand is of length 7cm?
Ans1) speed, v=st=2πrT=2×227×7×10-260×60=119×10-4=1.22×10-4m/s
<h2>
<em><u>Hope it helps</u></em></h2>
Answer:
8 KJ/ s
Explanation:
Heat pumps Transfer thermal energy through absorbing of heat that comes from cold region and then release to warmer area by utilizing external power.
The coefficient of performance known as COP provide the ratio of both heating and cooling that are supplied to required work.
✓QH=The rate at which heat is produced = ?
✓COP= Coefficient of performance of a residential heat pump = 1.6
✓ W(in)= power consumption= 5KW
QH=The rate at which heat is produced=[Coefficient of performance of a residential heat pump] × [power consumption]
= 1.6 × 5KW
=8 KJ/ s
<h2>
Answer: 277.777 m</h2>
Explanation:
The situation described here is parabolic movement. However, as we are told that the rock was<u> projected upward from the surface</u>, we will only use the equations related to the Y axis.
In this sense, the movement equations in the Y axis are:
(1)
(2)
Where:
is the rock's final position
is the rock's initial position
is the rock's initial velocity
is the final velocity
is the time the parabolic movement lasts
is the acceleration due to gravity at the surface of the moon
As we know , equation (2) is rewritten as:
(3)
On the other hand, the maximum height is accomplished when 
:
(4)
(5)
Finding :
(6)
Substituting (6) in (3):
(7)
(8) Now we can calculate the maximum height of the rock
(9)
Finally:
As we know that total work done by a force is given by
so it is product of force and displacement along same direction
as we can write it as
so it must be the product of force and displacement in same directions so correct answer must be
<u>B. in the same direction as the displacement vector and the motion.</u>
