4:chemical properties can only be observed when a substance changes into another substance.
5: physical properties such as color and shape are easy to observe
6: in a chemical change an altered substance forms
7: cooking or baking food will result in a chemical change
8: a melting ice cube is a physical change
9: the rusting of iron is a chemical change
10: water boiling is a scientific physical change
Explanation:
1. Movement of water, food and mineral salts in plants
2. Absorption of water by towels when wiping our bodies
3. It is used to absorb ink using a blotting paper or tissue
The answer is that it is constant. The relation between electric field and electric potential is given as, E= -gradient (V). The E, the partial rate of change of Electric potential, in the equation implies that the V, the partial differential of the potential of the three-dimensional space (assuming it is considered) is constant.
Answer:
Explanation:
Initial velocity of mailbag u = 2 m/s
acceleration downwards a = g = 9.8 m/s²
time t = 3 s
a ) final velocity v = ?
v = u + at
= 2 + 9.8 x 3
= 31.4 m /s
b )
s = ut + 1/2 g t²
s is relative displacement of mailbag
u = relative initial velocity of mailbag = 0
relative acceleration = g = 9.8 m /s²
time t = 3 s
s = 0 + 1/2 x 9.8 x 3²
= 44.1 m
relative displacement of mailbag = 44.1 m .
Answer:
a) The maximum potential difference the wet human body can take = 5.88 V
b) This value is very much lower than the normal voltage of household outlets (120 V) and isn't in the same range at all.
This means one should be very careful operating electrical appliances (even at home) while the body is wet.
Explanation:
From Ohm's law, V = IR
The resistance of the body when the body is wet = 1.2 kΩ = 1200 Ω
Maximum safe current that the body can withstand = 4.90 mA = 0.0049 A
Maximum voltage the body can withstand while wet = (Maximum safe current that the body can withstand) × (Resistance of the body when the body is wet) = 0.0049 × 1200 = 5.88 V
b) This value is still very much lower than the normal voltage of household outlets (120 V) and isn't in the same range at all.
This means one should be very careful operating electrical appliances (even at home) while the body is wet.
