# Search results

1. ### Final mark?

I just have a question that I'm hoping someone can help me with. I just finished a physics course where the final exam weighs at 40% of my final mark while the assignments weight at 60% which =100% total For my assignments I got a terrible 843.99 out of 1,408. I'm not quite sure what I got...
2. ### Work done and friction problem

A force of 52 N is applied to a 12 kg mass resting on a bench where the force of sliding friction is 15 N. The work done in overcoming friction while moving the object 24 m is w=fd w=(37N)(24m) w=888J Does this procedure seem correct ? :) Thank you!
3. ### Height of stairs

A 65.0 kg student climbs a set of stairs in 25.0 s with a power output of 95 W. What is the vertical height of the stairs? I came up with the formula: W=P x (delta t) W=95w(25.0s) 2375 Im not sure how this comes in to play: W = mg (delta h) Im really confused :|
4. ### Sound frequency

A 245 Hz sound with a wavelength of 1.41 m is projected into a narrow canyon. If the canyon is 1.50 km long, what time does it take an echo to be heard? How would I solve for this question? :)
5. ### Initial velocity

What formula would I use to find the initial velocity? An object is thrown vertically into the air and reaches a height of 30.0 m. Neglecting air friction, what was the object’s initial velocity? I dont quite remember how to do this. Is it 30.0m / 9.81[m/s]^2?
6. ### Verticle height of stairs

A 65.0 kg student climbs a set of stairs in 25.0 s with a power output of 95 W. What is the vertical height of the stairs? Im not quite sure where to start with this one?
7. ### Frequency and length

. If the speed of sound in air is 343 m/s and the frequency of the tuning fork is 225 Hz, what is the length of the air column shown in the diagram? wavelength= v ÷ f wavelength =343[m/s] ÷ 225[Hz] wavelength =1.52 m I'm not feeling this is right, what am I doing wrong? Is length and...
8. ### Students were testing their hearing range

In an experiment, students were testing their hearing range and found that it averaged about 25 Hz to 18 000 Hz. What are the wavelengths of sound waves producing these frequencies in air where the speed of sound is 343 m/s? Would I use the formula wavelength= velocity/ frequency...
9. ### How much work does gravity do on the car

A car of mass 1500 kg rolls down a hill for a distance of 150 m. If the road makes an angle of 15º with the horizontal, how much work is done on the car by the force of gravity? would I use the formula W=fdcosº w=(f)(150m)(15º) For force would I convert 1500kg into newtons and plug...
10. ### Calculate the power of the crane

A crane uses a force of 2.3 x 103 N of force to lift a steel ball 32.0 m in 1300 s, calculate the power of the crane. Would i use the equation: p=force x displacement /time (2.3x10^3n)(32m)/1300s?
11. ### Inital velocity

An object is thrown vertically into the air and reaches a height of 30.0 m. Neglecting air friction, what was the object’s initial velocity? What would the equation be for this question? I know that: Height: 30.0m Gravity: 9.81m/s I'm not quite sure what else I need to figure this...
12. ### Acceleration due to gravity

If the acceleration due to gravity changed to 9.9 m/s2, what possibly could have happened to the mass of Earth (Me) and/or the radius of Earth (re)? My answer is that the mass and radius would increase?
13. ### Asteroid orbit physics problem

An asteroid is orbiting around the sun at a distance of 4.2x 1011 m. If the Earth orbits around the Sun at a distance of 1.5 x 1011 m with a period of 3.2 x107 s, what is the period of the asteroid? Im thinking it was 9.0 x 10^7 s ?
14. ### Centripetal force

A 2.4 x 103 N force is necessary to keep a car and driver moving at a speed of 100 km/h through the middle of a highway curve that has a radius of 350 m. What is the mass of the car and driver? Im really confused on this question, I was told the formula should be something like FC=MV^2...
15. ### How do you find wavelength if your given only the speed?

How do you find wavelength if your given only the speed?
16. ### An asteroid is orbiting around the sun at a distance of 4.2

An asteroid is orbiting around the sun at a distance of 4.2  1011 m. If the Earth orbits around the Sun at a distance of 1.5  1011 m with a period of 3.2  107 s, what is the period of the asteroid?
17. ### Speed of sound wave in air

A sound wave produced by a smoke alarm 35.0 m away is heard 0.103 s after having been started by smoke in the air. The frequency of this sound wave is 1.02  103 Hz. Complete the following. a.Find the speed of this sound wave in air. b. Find its wavelength and period. The sound...
18. ### Wavelengths in a ripple tank experiment

In a ripple tank experiment, students generate water waves at a speed of 4.0 cm/s and a wavelength of 0.5 cm. If the waves are refracted into shallower water where their speed decreases to 3.0 cm/s, what is their new wavelength? What would the formula be for this question?
19. ### Size of the angle of incidence?

If the angle between an incident ray and a reflecting surface is 23°, what is the size of the angle of incidence? Im not quite sure what the formula for this would be, I cant find it in my book :| any help would be very much appreciated. Thank you
20. ### Wavelength formula help

If im given the measurement of 10cm between phases what is the wavelength? I couldnt find the formula for it in my book :S help?
21. ### What is the circumference of the track?

A student runs at a speed of 8.50 m/s on a circular track. If she accelerates a 1.03 m/s2, what is the circumference of the track? 8.5m/s*1.03m/s?
22. ### Force of water on falling bag

At an altitude of 315 m above a lake, a hot-air balloon pilot drops a 2.50 kg sandbag. If the bag comes to a stop 4.50 m below the surface of the lake, what force was applied by the water on it? I was thinking v= 2.50kg x 9.81km/h= 24.525m/s i cant remember how to get the force
23. ### Radius and speed

A student runs on a circular track that has a radius of 135 m. If she accelerates at 0.60 m/s2, what is her speed? a=V2/R? 0.62m/s2 /135m?? I think I def have the wrong formula, is anyone able to help me out to find speed?
24. ### Constant force

A barrel of oil with a mass of 65 kg is rolled down a 1.2 m ramp. Due to a constant force exerted on it, the barrel reaches a velocity of 4.2 m/s just on leaving the ramp. Find the constant force on the barrel while it is on the ramp and express your answer in the form of a sentence relating...
25. ### Force applied by water

At an altitude of 315 m above a lake, a hot-air balloon pilot drops a 2.50 kg sandbag. If the bag comes to a stop 4.50 m below the surface of the lake, what force was applied by the water on it? Mass:2.50kg velocity: 2.50kg*9.81m/s=61.31? I cant remember how to figure out what the time...
26. ### Exerted force 40N and 40N?

If a student out fishing pulls on a fish with a force of 40 N and the fish pulls back with a force of 40 N, what is the force exerted on the student and the fish at the same time? 40+40= 80N? is that correct?
27. ### Exerted force?

A 950 kg car starts from rest and reaches a velocity of 50.0 km/h in 8.50 s. If the driver has a mass of 75.0 kg, what force is exerted on the car and driver during this time interval? I am very confused on this question. I was thinking: 950kg+750.kg=1025 50.0/3.6 =13.88 +8.5 = 22.38s...