Final answer:
In Physics, when a lift accelerates upwards, the apparent weight on a weighing machine inside the lift increases. The girl's apparent mass is calculated by adding the lift's acceleration to Earth's gravitational acceleration and multiplying by her mass, resulting in an apparent weight of 660N or 66kg.
Step-by-step explanation:
The subject of the question is Physics, and it involves concepts related to Newton's second law of motion and the effects of acceleration on weight measurement.
When the girl whose mass is 55kg stands on a spring weighing machine inside a lift that is accelerating upwards with an acceleration of 2m/s2, the actual reading on the weighing machine will be higher than her normal weight due to the additional force exerted by the acceleration of the lift.
The apparent weight can be calculated using the formula F = ma, where m is the mass and a is the acceleration (which is the sum of gravitational acceleration and the lift's acceleration).
Therefore:
Apparent weight = m(g + a) = 55kg(10m/s2 + 2m/s2) = 55kg * 12m/s2 = 660N.
Since weight is mass times gravitational acceleration, and 1kg under Earth's gravity is 9.8N (in our case we approximate it to 10N for simplicity), we divide the apparent weight in newtons by 10N/kg to find the apparent mass:
Apparent mass = 660N / 10N/kg = 66kg.
The correct answer is A. 66kg.