Physics Answers

a ball is thrown horizontally with an initial speed of 10ms from an 80 m cliff.how long does it take to reach the ground?

5 m wire made of gold ( ρgold = 2.4 x 10−8 ) has a cross-sectional area of 2 mm.

Calculate the voltage if a 32 A current runs through the wire.

Water is flowing in a hose with a velocity of 1.5 m/s and a pressure of 3 kPa. At

    the nozzle the pressure decreases to atmospheric pressure (101300 Pa), there

    is no change in height. Use the Bernoulli equation to calculate the velocity of the

   water exiting the nozzle. The density of water is 1000 kg/m3 and gravity g is 9.8 

    m/s2.

A balloon is fitted over the open end of a glass beaker that contains water.

The beaker is placed over a flame, which heats the water. At the same time,

the balloon is squeezed, so that it deflates. What are the correct signs for the

heat and work changes to the beaker and balloon system?

O A. -Q.+w

O B. +Q,+W

O C. -Q,-W

O D. +0. -w

 Calculate the strength of an electric field 1.2 m away from a point charge of 7.4 x 10-5C.

Calculate the magnitude of force that would act on an object carrying a charge of 3.2 x 10-5C if it was placed in a magnetic field with a strength 4.27 x 104 N/C.

What is my power rating if I can run up three storeys in 20s, given that each storey is 4m high and I have mass of 80kg

A square coil (0.40 m²) of wire consists of 70 loops. The magnetic field is perpendicular

to the face of the coil and decreases at a rate of 0.025 T/s. What is the magnitude of

the induced electromotive force in the loop?

A circular coil with 100 turns and a radius of 0.10 m is placed in a uniform magnetic

field so that it is perpendicular to the plane of the coil. The field changes uniformly

from zero to 0.4T in 2 seconds. Calculate the induced emf.

Resistor consist of R1=4, R2= 4.5 R3= 12

Resistor R3 connected in parallel with R2 .

1 )draw a the circuit diagram

2 )calculate the voltage across R3 if the applied voltage is 12V .

3 ) calculate the current passing R1 and R 3