Question

A person is measuring his weight by standing on a
weighing machine inside a lift. When the lift is at
rest, the machine shows his weight to be 55 kg. In
between the floor when the lift is moving up with a
constant speed of 10 km/hr, he again measures his
weight, which is
a)55 kg b)65 kg c)50 kg d)45 kg​

Answer 1

Answer:

b) 65kg

Explanation:

weight of the person=55kg

v=10km/h

since the weight adds up as the lift moves up in constant speed, the weight will be more than the actual weight.

therefore,

weight of the person=55+10

=65kg

therefore the option is b)65kg

Answer 2

Given,

At rest machine shows his weight=55kg

Speed of the lift=10km/hr

To Find,

His weight when lift is moving.

Solution,

weight of the person when lift is rest is =55kg

Speed with which lift is moving up, v=10km/h

But the lift is moving upwards with a constant speed.

So its acceleraration will be zero.

Therefore,

weight of the person will be remain same as it is.

Hence, his weight will be 55kg(Option A).