Qstnid -A-7-a Classroom Demonstration Of Newton’s First Law Is As Follows : A Glass Is Covered With A Plastic Card And A Coin Is Placed On The Card. The Card Is Given A Quick Strike And The Coin Falls In The Glass. (A) Should The Friction Coefficient Between The Card And The Coin Be Small Or Large? (B) Should The Coin Be Light Or Heavy? (C) Why Does The Experiment Fail If The Card Is Gently Pushed? (A) Should The Friction Coefficient Between The Card And The Coin Be Small Or Large? (B) Should The Coin Be Light Or Heavy? (C) Why Does The Experiment Fail If The Card Is Gently Pushed? - 06: Friction

with Solutions -

#7
A classroom demonstration of Newton’s first law is as follows : A glass is covered with a plastic card and a coin is placed on the card. The card is given a quick strike and the coin falls in the glass. (a) Should the friction coefficient between the card and the coin be small or large? (b) Should the coin be light or heavy? (c) Why does the experiment fail if the card is gently pushed? (a) Should the friction coefficient between the card and the coin be small or large? (b) Should the coin be light or heavy? (c) Why does the experiment fail if the card is gently pushed?
Ans : (a) The coefficient of friction between the card and the coin should be small. (b) The coin should be heavy. (c) If the card is pushed gently, the experiment fails because the frictional force gets more to time to act and it may gain some velocity and move with the card. (a) The coefficient of friction between the card and the coin should be small. (b) The coin should be heavy. (c) If the card is pushed gently, the experiment fails because the frictional force gets more to time to act and it may gain some velocity and move with the card.

#7-a
Should the friction coefficient between the card and the coin be small or large?
Ans : The coefficient of friction between the card and the coin should be small.

#7-c
Why does the experiment fail if the card is gently pushed?
Ans : If the card is pushed gently, the experiment fails because the frictional force gets more to time to act and it may gain some velocity and move with the card.