Physics: Post your doubts here!

[princess Anu]

I found it in a topical past papers book. The year was not written.

:/ I don't think A shud be the answer...
Can u show me ur complete solution please or see mine.. tell me anything is wrong with it :s

 

[69ermalik007]

Can somebody help me with these questions?

 

[princess Anu]

Why is B wrong? Ans is D

Ahmed Aqdam

 

[waqas123]

:/ I don't think A shud be the answer...
Can u show me ur complete solution please

KE Trolley(1/2 * m * v^2) + KE Mass = Loss in GPE (mgh)
1/2 x 1.5 x v^2 + 1/2 x 0.5 x v^2 = 0.5 x 9.81 x 1.0
v^2 = 4.905

KE Trolley = 1/2 x m x v^2 = 1/2 x 1.5 x 4.905 = 3.7 J

Note: Velocity of both objects is same.

 

[princess Anu]

Oh yeahh, I was adding up their K.E's, lol -.-.
Thanks a lot

KE Trolley(1/2 * m * v^2) + KE Mass = Loss in GPE (mgh)
1/2 x 1.5 x v^2 + 1/2 x 0.5 x v^2 = 0.5 x 9.81 x 1.0
v^2 = 4.905

KE Trolley = 1/2 x m x v^2 = 1/2 x 1.5 x 4.905 = 3.7 J

Note: Velocity of both objects is same.

 

[waqas123]

View attachment 54671 Why is B wrong? Ans is D

Year?

 

[princess Anu]

Year?

J2000

 

[nehaoscar]

How to do this one??

 

[nehaoscar]

How??

 

[princess Anu]

WHY is C wrong? ?

 

[princess Anu]

View attachment 54674
How to do this one??

deltaP= change in Momentum
p= pressure

 

[nehaoscar]

Why C?

 

[nehaoscar]

View attachment 54673 WHY is C wrong? ?

Voltage would stay the same
Try using some values
eg: V = 100V and R = 10 to start with
I = 10
so pd = IR = 100 (same as supply)

Then change R = 20
I = 5
pd = 100 (still the same)

 

[Ahmed Aqdam]

View attachment 54676
How??

Resultant Moment= Clockwise moment - anticlockwise moment
4*0.4-2*0.1=1.4 N m

View attachment 54673 WHY is C wrong? ?

There is no resistance due to plates so p.d. will remain same.

 

[nehaoscar]

How???

 

[Ahmed Aqdam]

View attachment 54681
Why C?

As percentage uncertainty is same for all values, the actual uncertainty will be least when θ is least.
Percentage uncertainty= Actual uncertainty/Value*100 so if actual uncertainty is less than value should also be less.

 

[nehaoscar]

Why C.. why not B?

 

[nehaoscar]

Why C ?? please explain!

 

[Boss201]

A car is travelling with uniform acceleration along a straight road. The road has marker posts every 100m. When the car passes one post , it has a speed of 10m/s and , when it passes the next one , its speed is 20m/s

What is the car acceleration ?
A.0.6m/s^2
B.1.5m/s^2
C.2.5m/s^2
D.6.0m/s^2

(from marking scheme answer is (B:1.5m/s^2)[June 2004 paper 1 number 7]

 

[nehaoscar]

A car is travelling with uniform acceleration along a straight road. The road has marker posts every 100m. When the car passes one post , it has a speed of 10m/s and , when it passes the next one , its speed is 20m/s

What is the car acceleration ?
A.0.6m/s^2
B.1.5m/s^2
C.2.5m/s^2
D.6.0m/s^2

(from marking scheme answer is (B:1.5m/s^2)[June 2004 paper 1 number 7]

u = 10 , v = 20 , s = 100
using v^2 = u^2 + 2as
a = 1.5