Answer:
efficiency of a machine is less than 100% because some part is energy is utilized to overcome some opposing forces like friction which is wasted as heat ,sound energy etc
Explanation:
Metals are malleable and ductile.
Metals are good conductors of heat and electricity.
Metals are lustrous (shiny) and can be polished.
Metals are solids at room temperature (except mercury, which is liquid).
Metals are tough and strong.
hope this helps!
Answer:
The answer is "telescopes".
Explanation:
Throughout ancient times, astronomical observatories have indeed been available, and so many historical locations were reserved for astronomical observations. All contemporary astronomers lacked within those older telescopes were lenses until 1610. A telescope is indeed an instrument used to view far-off objects. Telescopes often are being used to look at planets and stars.
Answer:
The difference in the length of the bridge is 0.42 m.
Explanation:
Given that,
Length = 1000 m
Winter temperature = 0°C
Summer temperature = 40°C
Coefficient of thermal expansion 
We need to calculate the difference in the length of the bridge
Using formula of the difference in the length
Where, 
= temperature difference
=Coefficient of thermal expansion
L= length
Put the value into the formula
Hence, The difference in the length of the bridge is 0.42 m.
