HCl + NaOH -> H2O + NaCl
CaCO3 + KI -> K2CO2 + CaI2
AlF3 + Mg(NO3)2 -> Al(NO3)3 + MgF2
Answer : The correct option is, (D) A machine does 400 joules of work in 5 seconds.
Explanation :
Power : It is defined a the rate of doing work per unit time.
Formula used :

where,
P = power
w = work done
t = time
Now we have to determine the rate of power for the following options.
(A) A machine does 200 joules of work in 10 seconds.

(B) A machine does 400 joules of work in 10 seconds.

(C) A machine does 200 joules of work in 5 seconds.

(D) A machine does 400 joules of work in 5 seconds.

From this we conclude that, a machine does 400 joules of work in 5 seconds has the highest rate of power.
Hence, the correct option is, (D)
Answer;
= 3.86 × 10^8 Meters
Explanation;
-The distance between the Earth and the moon is 386000 km
But; 1 km = 1000 m
Therefore; 386000 km will be equivalent to;
= 386000 × 1000
= 386000000 m
= 3.86 × 10^8 meters
Answer:
183333 Pa
Explanation:
The weight of the football player is : 550 N ,thus the force the player exerts on the floor is 550 N
The area of blades in contact with the floor is = 30cm² = 0.003 m²
Pressure = Force / Area
Pressure = 550 / 0.003
Pressure = 183333 Pa
Answer:
the initial velocity of the ball is 104.67 m/s.
Explanation:
Given;
angle of projection, θ = 60⁰
time of flight, T = 18.5 s
let the initial velocity of the ball, = u
The time of flight is given as;

Therefore, the initial velocity of the ball is 104.67 m/s.