Question

A car moves with speed 60 km/h for 1 hour in east
direction and with same speed for 30 min in south
direction. The displacement of car from initial
position is
(1) 60 km
(2) 3013 km
(3) 30/5 km
(4) 602 km​

Answer 1

Correct Question

A car moves with speed 60 km/h for 1 hour in east

direction and with same speed for 30 min in south

direction. The displacement of car from initial

position is

(1) 60 km

(2) 3013 km

(3) 30√5 km

(4) 602 km

Solution -

Given that, a car moved with speed of 60 km/hr for 1 hour in East direction.

Distance travelled by the car in East direction = speed × time

= 60 × 1 = 60 km

Similarly,

With a se speed i.e. 60 km/hr it travels in South direction for 30 min.

Now, time = 30 min = 30/60 = 1/2 hour

Distance travelled by the car in South direction = speed × time

= 60 × 1/2 = 30 km

We have to find the Displacement of the car from the initial position.

Now,

Displacement of the car from initial position = √[(distance travelled by car in East direction)² + (distance travelled by the car in South direction)²]

= √[(60)² + (30)²]

= √(3600 + 900)

= √4500

= √900(5)

= 30√5

Therefore, the displacement of the car from the initial position is 30√5 km.

Option 3) 30√5 km

Answer 2

CORRECT QUESTION:

A car moves with speed 60 km/h for 1 hour in east direction and with same speed for 30 min in south direction. The displacement of car from initial position to final position is .

(1) 60 km

(2) 3013 km

(3) 30√5 km

(4) 602 km

Note : In the question the bolded text is for correction

GIVEN:

• Car is moving for 1 hour in East direction with a speed of 60 km/h
• The car again is moving with constant speed in South direction for 30 min = 0.5 hr

TO FIND:

• Displacement from initial point to final point

SOLUTION:

Note: Refer the attachment

Finding distance travelled in East direction & south direction by using

Distance (d) = speed × time

d = 60 × 1

d = 60 km

_________________

d = 60 × 0.5

d = 30 km

Using Pythagoras theorem

Pythagoras theorem : Sum of square of base and height equal to square of hypotenuse

(Hypotenuse)² = (Base)² + (Height)²

Simplifying

Hypotenuse = √(Base)² + (Height)²

Here,

• Hypotenuse = Displacement
• Base = Distance travelled in East direction
• Height = Distance travelled in South direction

Substituting the values we get

Displacement = (Distance travelled in East direction)² + (Distance travelled in South direction)²

Displacement = √60² + 30²

Displacement = √3600 + 900

Displacement = √4500

Displacement = 30√5

Hence, Displacement from initial point to final point = 30√5 km