Physics Answers

Block A is at rest on a frictionless incline. It is attached to block B over a pulley. Block A has mass of 4.50 kg and block B has a mass of 5.50 kg. When the system is released, block A moves up the incline 1.5 m, after which it has a speed of 3.00 m/s.

Flashlight batteries is having electro-motive force of 1.5 v and internal resistance of one owns are connected to a resistor

of 5 ohms calculate the current in this resistor if the cell are connected to series or parallel

3. Seat belt

In the event of an accident, a car driver (80kg) will use the seat belt (and because of

the crumple zone) over a distance of 40cm from 72 km / h to a standstill

braked. This takes 40 ms = 0.040 s.

a) Calculate the braking force on the driver.

b) When supporting on the steering wheel, you can "apply" a maximum of 500 N.

Would that be enough to protect yourself without a seat belt?

Estimate the number of hairs on your head.

I used an interesting estimation which is to say that 1cm² = 100 hairs and to estimate the head as sphere with radius of r = 10 cm.

Am I right to tell an estimation like this?

If not what is right??

A futile task is proverbially said to be “like trying to empty the ocean

with a teaspoon.” Just how futile is such a task? Estimate the number of

teaspoonfuls of water in the Earth’s oceans.

And,

Estimate the time that might be taken to empty all oceans in the Earth. Give your answer with centuries and seconds.

a) Define the elastic modulus. Explain the different types of elastic modulus.

b) State and explain Einstein's Photoelectric Effect theory.

c) If 12𝑁 force is applied to a fluid of cross-section 5.34 𝑐𝑚2 with a shearing rate of 0.7 𝑠 −1 then find the viscosity of the fluid

Find the total energy of a moving object of mass 6.3 𝑘𝑔 and momentum

11.5 × 106 𝑘𝑔𝑚𝑠

−1

.

A wire of length 7 𝑚 and radius 2.37 𝑚𝑚 is stretched by a load of 12370 𝑔𝑚 and

increased by 1.78% of the original length. Find the stress, strain, and Young’s

modulus of the material of the wire.

A capillary tube with an inside radius of 638 𝑛𝑚 can support a 100 𝑚𝑚 column of

liquid that has a density of 820 𝑘𝑔𝑚−3. The observed contact angle is 12.5°. Find

the surface tension of the liquid for ℎ = 20 𝑐𝑚. need to solution

The radius of a silver bar is 30 𝑐𝑚. What force is required to stretch the bar by

12.7% of its length where Young’s modulus is 𝑌 = 7.25 × 1010 𝑁𝑚−2