Answer : 
Explanation :
It is given that,
Mass of the engine, m = 30 kg
Thrust is equivalent to the force acting perpendicularly and it is F = 300 N
According to Newton's second law of motion :

a is the acceleration of the engine.



So, the acceleration of the engine is
.
Hence, this is the required solution.
Answer:
b. The internal resistance must be much smaller than the other resistances in the circuit.
Explanation:
Ammeter is used to measure the current flowing through a circuit. It is connected in series configuration with the load. In such a scenario the resistance of the ammeter should be negligible so as to make sure that the voltage drop across the resistance of ammeter is zero and it shows the correct reading of the current in the circuit.
Answer:
23. 4375 m
Explanation:
There are two parts of the rocket's motion
1 ) accelerating (assume it goes upto h1 height )
using motion equations upwards

Lets find the velocity after 2.5 seconds (V1)
V = U +at
V1 = 0 +5*2.5 = 12.5 m/s
2) motion under gravity (assume it goes upto h2 height )
now there no acceleration from the rocket. it is now subjected to the gravity
using motion equations upwards (assuming g= 10m/s² downwards)
V²= U² +2as
0 = 12.5²+2*(-10)*h2
h2 = 7.8125 m
maximum height = h1 + h2
= 15.625 + 7.8125
= 23. 4375 m
the answer is CaO because that's what my homework says is correct