+91-8076753736[email protected]
logo
logo
-->

Is Matter Around Us Pure

Question
CBSEENSC9005943
Wired Faculty App

A motorcar is moving with a velocity of 108 km/h and it takes 4 s to stop after the brakes are applied. Calculate the force exerted by the brakes on the motorcar if its mass along with the passengers in the motorcar is 1000 kg.

Solution

Here,
Initial velocity of motorcar, u = 108 km h-1 
                                            equals space 108 space cross times space 5 over 18 space equals space 30 space ms to the power of negative 1 end exponent
The brakes are aplied and motorcar comes to rest.
So,
Final velocity= 0
Time taken for the motorcar to stop, t = 4s
MAss of the motorcar, m = 1000 kg
therefore  Force, 
straight F equals space straight m open parentheses fraction numerator straight v minus straight u over denominator straight t end fraction close parentheses space equals space 1000 space open parentheses fraction numerator 0 minus 30 over denominator 4 end fraction close parentheses space equals space minus 750 space straight N.

The negative sign shows that the force exerted by the brakes is opposite to the direction of motion of motorcar. 

Some More Questions From Is Matter Around Us Pure Chapter

Which separation techniques will you apply for the separation of the following?

Different pigments from an extract of flower petals.

Which separation techniques will you apply for the separation of the following?

Butter from curd.

Which separation techniques will you apply for the separation of the following?

Oil from water.

Which separation techniques will you apply for the separation of the following?

Tea leaves from tea

Which separation techniques will you apply for the separation of the following?

Iron pins from sand.

Which separation techniques will you apply for the separation of the following?

Wheat grains from husk

Which separation techniques will you apply for the separation of the following?


Fine mud particles suspended in water.

Write the steps you would use for making tea. Use the words—solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).

Substance Dissolved

Temperature in K

283

293

313

333

353

Potassium nitrate

21

32

62

106

107

Sodium chloride

36

36

36

37

37

Potassium chloride

35

35

40

46

54

Ammonium chloride

24

37

41

55

66


What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?

Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.

Substance Dissolved

Temperature in K

283

293

313

333

353

Potassium nitrate

21

32

62

106

107

Sodium chloride

36

36

36

37

37

Potassium chloride

35

35

40

46

54

Ammonium chloride

24

37

41

55

66


Mock Test Series

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation