Explanation:
A student solving for the acceleration of an object has applied appropriate physics principles and obtained the expression :

Where


m = 7 kg
So, the correct step for obtaining a common denominator for the two fractions in the expression in solving for a is (a) and the value of a is :


Hence, the correct option is (a).
Answer:
Balances and Scales
A balance compares an object with a known mass to the object in question. One example of a balance is the triple beam balance. The standard unit of measure for mass is based on the metric system and is typically denoted as kilograms or grams.
battery
Explanation:
Electromagnets can be created by wrapping a wire around an iron nail and running current through the wire. The electric field in the wire coil creates a magnetic field around the nail. In some cases, the nail will remain magnetised even when removed from within the wire coil
Answer:
The momentum of bath cars is 40000 Ns which make the difficulty to stop each car in aspect of fprce is the same.
Explanation:
Momentum (P) =mass(m) × velocity (v)
For car A,
P = m × v = 1000 × 40 = 40000 Ns
For car B,
P = m × v = 4000 × 10 = 40000 Ns
Force (F) = Momentum change(ΔΡ)/ time taken(t)
F = ΔΡ/t
When stopping the car the momentum changes from 40000 Ns to 0
So momentum change in both cars is the same. So to stop the two cars in a given time (t) you need the same force, which means you will feel same difficulty.