Physics: Post your doubts here!

[hellodjfos;s'ff]

Is 27 B?

C

 

[A*****]

The answer to this is correct to the smallest division but like in chem won't we take it to the nearest HALF OF THE SMALLEST DIVISION?

 

[A*****]

By ref to this question, plz explain that in the equation P=Fv, which force do we take

 

[hellodjfos;s'ff]

View attachment 64162

By ref to this question, plz explain that in the equation P=Fv, which force do we take

The force in P=Fv is meant to be the resultant force. In this question, there is no mention of other forces so we take the resultant force as 180N.

 

[A*****]

The force in P=Fv is meant to be the resultant force. In this question, there is no mention of other forces so we take the resultant force as 180N.

But we derive this equation from the equation of work right? So shouldn't the force be the one in the direction of work being done??

 

[hellodjfos;s'ff]

But we derive this equation from the equation of work right? So shouldn't the force be the one in the direction of work being done??

That is true, but power is a scalar quantity so the direction of the force or velocity don't matter.

 

[hellodjfos;s'ff]

This question makes no sense. Can someone solve it?

 

[IN NEED OF HELP]

In still air, a bird can fly at a speed of 10 m s–1. The wind is blowing from the east at 8.0 m s–1. In which direction must the bird fly in order to travel to a destination that is due north of the bird’s current location?
A 37° east of north
B 37° west of north
C 53° east of north
D 53° west of north

 

[Kanekii]

Is ans DD?

 

[khadijaimran]

i cant seem to understand these types of questions please help

 

[Kanekii]

This question makes no sense. Can someone solve it?

A?

 

[hellodjfos;s'ff]

In still air, a bird can fly at a speed of 10 m s–1. The wind is blowing from the east at 8.0 m s–1. In which direction must the bird fly in order to travel to a destination that is due north of the bird’s current location?
A 37° east of north
B 37° west of north
C 53° east of north
D 53° west of north

So they want the destination to be north of the bird's current location meaning that the resultant velocity must be vertically upwards. You draw a vector triangle based on the info that the resultant is directly upwards and the wind is blowing from the east. Then you use sin, cos or tan to find the angle. I would use sin since no further calculations would be needed to find the answer using sin. The angle will turn out to be 53, and you can determine the direction using your vector triangle(it will turn out to be west of north making the answer D).

 

[hellodjfos;s'ff]

A?

It's C. The question is really weird

 

[Kanekii]

i cant seem to understand these types of questions please help

BB?

 

[hellodjfos;s'ff]

Is ans DD? View attachment 64164

Yup, answer is D because x=lamda(D)/a. So fringe separation is proportional to the lamda, so if you use a greater wavelength, you get greater fringe separation.

 

[Kanekii]

Yup, answer is D because x=lamda(D)/a. So fringe separation is proportional to the lamda, so if you use a greater wavelength, you get greater fringe separation.

What if the width of the slits increased would that effect fringe separation?

 

[Hisham Khan]

 

[hellodjfos;s'ff]

i cant seem to understand these types of questions please help

The increase in current suggests that the total resistance of the circuit increased(R=V/I). Now the only way the resistance can increase is through the variable resistor. So the resistance of the variable resistor was increased, and you can determine how much pd it takes up using the potential divider formula,(r1/r1+r2)*Vtotal. You can use some values to figure out that the pd of the variable resistor would increase while pd for fixed resistor would decrease. So the voltmeter readings on Q increase and for P it decreases(B).

 

[hellodjfos;s'ff]

What if the width of the slits increased would that effect fringe separation?

Width of slits don't effect anything in the double slit formula. Width of the slits only impacts the intensity of the wave/fringes.

 

[IN NEED OF HELP]

The three forces acting on a hot-air balloon that is moving vertically are its weight, the force due to air resistance and the upthrust force. The hot-air balloon descends vertically at constant speed. The force of air resistance on the balloon is F. Which weight of material must be released from the balloon so that it ascends vertically at the same constant speed?
A F
B 2F
C 3F
D 4F