Practicals

Question 1

How can we determine the spring constant/stiffness of a spring

Answer 1

• Fix the top of the spring to a clamp on a retort stand. Also fix a ruler next to it, with the zero mark lined up with the bottom of the spring.

For accurate measurements make sure ruler is as close to the spring as possible and get on eye level to reduce parralax error.

Add slotted masses on a hanger to the spring to change the force/tension. Calculate the force from weight using F=mg. Then plot force against extension which should show a directly proportional relationship (linear snd through origin)

Find the gradient of the line,this is equal to the spring constant in N/m or N/m depending on what unit was used.
F=ke (force = spring constant × extension)

Question 2

How can we verify newton’s second law (Force = mass × acceleration)

Answer 2

Attached slotted masses to a trolley on a track, so that they hang over a pulley.

Let the trolley move due to the weight of the masses - its will flag pass through two light/photogates to a datalogger, which will calculate acceleration.

Change the force by removing the masses and adding them onto the hanger. This is crucial as the total mass being accelerated (trolley + masses) must remain constant.

Get the force by multiplying the mass by g every time and plot force against acceleration which should show a directly proportional relationship

Question 3

How can we calculate wave speed by measuring frequency and wavelength of waves

Answer 3

With a signal generator (tells us frequencies) connected to a dipper inside a ripple tank, project the image of ripple tank onto paper or screen, using a ruler measure the length of of around 10 waves then divide by 10 to get the wavelength.
-Repeat for different frequencies.
(You can also count the number of waves reaching the end of tank in 10s and divide by ten for the frequencies of waves per second)

Use wavespeed = frequency x wavelength

Question 4

How can we make counting the waves easier in the practical for wavespeed

Answer 4

The oscillator creating the waves being connected to a strobe light so the waves appear stationary on the screen.

Question 5

What is the (wave) 2nd practical for the stationary wave on spring

Answer 5

Start with getting an oscillator/vibration generator to produce a stationary wave on a spring with masses on the end over a pulley to provide some tension.

We need to vary the frequencies until we get the simplest stationary wave formed on the string- one loop- and at this point the length of the spring to the pulley or the bridge is equal to half the wavelength of the wave. Use wavespeed = frequency x wavelength, this should remain constant