which of the following devices is more precise ?
a) a vernier callipers with 10 divisons on the sliding scale b) a screw guage of pitch 1 mm and 100 divisos on the circular scale .

A screw gauge has a pitch of 1.0 mm and 200 divisions on the circular scale. Do you think it is possible to increase the accuracy of the screw gauge arbitrarily by increasing the number of divisions on the circular scale?

A man of mass 70 kg stands on a weighing scale in a lift which is moving (a) upwards with a uniform speed of 10 m s^1 (b) downwards with a uniform acceleration of 5 m s^2, upwards with a uniform acceleration of 5 m s-^1z. What would be the readings on the scale in each case? What would be the reading if the lift mechanism failed and it hurtled down freely under gravity?