Answer:
The measurement which is the most precise is 104.6 °C.
Explanation:
The measurement which is most precise must be very close to the actual value of the temperature.
Thus, the unit which have less value of the |Δx| (error) must be most precise.
Thus,
Actual value = 105.1 °C
Value = 103.7 °C
<u>|Δx| = 1.4 °C</u>
Value = 108.4 °C
<u>|Δx| = 3.3 °C</u>
Value = 105.8 °C
<u>|Δx| = 0.7 °C</u>
Value = 104.6 °C
<u>|Δx| = 0.5 °C</u>
<u>Thus, The measurement which is the most precise is 104.6 °C.</u>
Question: How fast was the arrow moving before it joined the block?
Answer:
The arrow was moving at 15.9 m/s.
Explanation:
The law of conservation of energy says that the kinetic energy of the arrow must be converted into the potential energy of the block and arrow after it they join:
where 
is the mass of the arrow, 
is the mass of the block, 
of the change in height of the block after the collision, and 
is the velocity of the arrow before it hit the block.
Solving for the velocity , we get:
and we put in the numerical values
,
and simplify to get:
The arrow was moving at 15.9 m/s
A 1.5 kg bird is gliding at a height of 12 m with a speed of 3.8m/s. The kinetic energy of the bird is 10.83 joules.
Explanation:
Kinetic energy can be defined as,The kinetic energy (KE) of an object is the energy that the object possesses due to its motion.
The Kinetic energy can be calculated by using formula,
Kinetic Energy: KE = 1/2 (mv 2)
Where, m = Mass, v = Velocity.
Here in this case the bird mass is 1.5kg and is gliding with velocity 3.8m/s
hence, KE= 1/2*(1.5)×(3.8)^2
=0.5×1.5×3.8×3.8
=10.83Joules
Answer:
Why do metals conduct heat so well? The electrons in metal are delocalised electrons and are free moving electrons so when they gain energy (heat) they vibrate more quickly and can move around, this means that they can pass on the energy more quickly.
Concave makes things smaller and convex makes things bigger
