Answer:
the crown was not made of pure gold
Explanation:
Mass of gold = weight in air/ g = 7.84N/10ms-2= 0.784 Kg or 0.8Kg
From Archimedes principle:
Upthrust= weight in air- weight in a fluid
Upthrust= volume × density × g
Note density of water = 1000kgm-3
7.84-6.84= V × 1000kgm-3×10ms-2
V= 1/10000= 1×10-4 m^3
Density = mass/ volume= 0.8/1×10-4
= 8×10^3 Kgm-3
But we know the density of gold to be 19.3 ×10^3 kgm-3
Hence the crown was not made of pure gold
A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.
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A. Thermal energy
Thermal energy is heat energy, therefore the hotter a solid is the more thermal energy it has.
C. Volume
When an object gets hotter, it expands. This is becuase the particles vibrate more and so are less compact.
Answer:
The maximum height reached by the ball is 2.84 m
Explanation:
Given;
initial velocity of the soccer, u = 13 m/s
angle of projection, θ = 35°
The maximum height reached by the ball = ?
Apply the following kinematic equation, to determine the maximum height reached by the ball.
Maximum height (H) is given as;
Therefore, the maximum height reached by the ball is 2.84 m
Answer:
0.459 Tesla
Explanation:
Faraday's law:
Φ= NAB
V = N Δ (BA) /Δt
the change in BA
was: BA = 0 because initially B was zero.
V=IR
IR = N B A /Δt
q / Δt ×R = N B A / Δt
Or: B = q R / NA = 8.87 x 10^-3 × 45.0 / 1850×4.7 x 10^-4 =
= 0.459 Tesla
