Answer:
C₂ = 2.22 KJ/kg °C
Explanation:
Since, both objects are in thermal contact. Therefore, the law of conservation of energy tells us that:
where,
m₁ = mass of ice = 1 kg
C₁ = specific heat of ice = 2.04 KJ/kg.°C
ΔT₁ = Change in Temperature of Ice = -8.88°C - (-24°C) = 15.12°C
m₂ = mass of metal block = 1 kg
C₂ = specific heat of metal = ?
ΔT₂ = Change in Temperature of Metal Block = 5°C - (-8.88°C) = 13.88°C
Therefore, using these values in the equation, we get:
<u>C₂ = 2.22 KJ/kg °C</u>
The rule to get the average speed is as follows:
average speed = average distance / average time
We are given that:
distance = 250 m
time = 110 sec
Substitute with the givens in the above equation to get the average speed as follows:
average speed = 250/110 = 25/11 meters/sec
Answer:
The acceleration of the sprinter is 1.4 m/s²
Explanation:
Hi there!
The equation of position of the sprinter is the following:
x = x0 + v0 · t + 1/2 · a · t²
Where:
x = position of the sprinter at a time t.
x0 = initial position.
v0 = initial velocity.
t = time.
a = acceleration.
Since the origin of the frame of reference is located at the starting point and the sprinter starts from rest, then, x0 and v0 are equal to zero:
x = 1/2 · a · t²
At t = 9.9 s, x = 71 m
71 m = 1/2 · a · (9.9 s)²
2 · 71 m / (9.9 s)² = a
a = 1.4 m/s²
The acceleration of the sprinter is 1.4 m/s²
The formula for the speeder should beV1 = d1/t1whereas the formula for the police car is d2 = vo t2 + 1/2 at2^2 where a is equal to 2.44 m/s2. when the overtaking takes place, d1 and d2 are the same, so as t1 and t2
30t = 1/2 *2.44*t2t is equal to 24.59 seconds.d then is equal to 737.70 meters
Answer:
15 kJ
Explanation:
We need to know the following;
what is activation energy?
- Activation energy is the minimum energy required by reactants for a chemical reaction to take place.
What are catalysts?
- Catalysts are molecules or substances that speed up the rate of a chemical reaction.
- In other words, catalysts increase the speed at which products are formed from reactants.
How do catalysts speed up reactions?
- Catalysts speed the rate of chemical reactions by lowering the activation energy of the reactants.
- When activation energy is lowered, reactants require less energy for the reaction to occur which easily achieved making the reaction proceed faster.
- Therefore, in presence of a catalyst, the new activation energy should be lower than the initial value of activation energy.
