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1. Distance and time

i need some help with this: the distance d that a certain particle moves may be calculated from the expression d=at+bt^2, where a and b are constants; and T is the elapsed time. complete the following statement: the dimensions of the quantities a and b are..., respectively help please i...
2. Gravity help

If an object is thrown vertically upward on the moon how many times higher will it go than it would on earth if they both have the same initial vel. Acceleration on moon is 1/6 of what it is on earth I need some help on solving this. Thank You
3. Converting mph

i need some help on a problem... does anyone know how to convert 65mph into ft/s and km/h? i would appreciate it THANKS! =)
4. Force and Work

hi i need help on two of my homework problems one on work and the other on force As you walk, there is a static frictional force between your shoes and the ground. Is any work done? Explain your answer. If three objects exert forces on a body, can they all do work at the same time? Explain...
5. A Couple More Simple Think critically and Explain Questions

Think and Explain 1. Why is it important that the resistance of an extension cord be small when it is used to power an electric heater? 2. Will the current on a light bulb connected to 220V be more or less than when the same light bulb is connected to 110V? How much? 3. In 60- Hz...
6. Simple Think Critically and Explain Question

Think and Explain Is this label on a household product cause for concern? "Caution: This product contains tiny electrically charged particles moving at the speeds of 10000000 km per hour" can someone please help me with this problem I would appreciate it Thanks!!:smile:
7. Simple dB question

hi, I'm having trouble with a question and i was wondering if anyone can help me out. "To a person who is hard of hearing, normal conversation (60dB) sounds like a soft whisper. What increase in sound levels (in dB) must a hearing aid provide? How many times must the sound wave pressure be...
8. Simple echo question

i need help on the following problem: "carol drops a stone into a mine shaft 122.5 m deep. How soon after she drops the stone does she hear it hit the bottom of the shaft?" i know that the acceleration is 9.8m/s^2 but i can't use it as speed in the speed=distance/time equation please help me...
9. DB question

hi, i need help in understanding something on sound. if admam works near a jet plane that is taking off and experiences the sound level of 150dB. then the protectors to reduce the sould level to that of a chain saw, what decrease in dB is needed? i think it's 40 but i am not sure. and also if...
10. Physics concept

hi my math teacher ask us this the other day..."in the military, as marching soldiers approach a bridge, the command route step is given. the soldiers then walk out of step with each other as they cross the bridge. explain." i don't understand what she means at all. is it even a physics concept...
11. Speed for lightning and thunder

i don't understand how you can estimate how far the lightning flash is from you by counting the seconds betw the flash and thunder, then divide by three to result in the distance in kilometers. can someone please explain where does the logic that resulted in this rule? i don't understand why it...
12. Simple question but still can't figure it outsound

i am having trouble with this question" if you clap your hands the echo from a distant wall 0.20s later, how far away is the wall?" how do you do this without the speed given to substitute into the speed= distance/time equation?
13. Simple acceleration problem

HI!! i need help on this problem..... A 60kg and a 40kg girl uses an elastic rope while engaged in a tug a war on the icy frictionless surface. If the acceleration of the girl towards the boy is 3.0m/s/s, determine the magnitude of acceleration of the boy to the girl. Please help if you...
14. Simple force question

hi this is my first year in physics and i am already confused on it. I really need help on the following question: "The force of -9000 N is used to stop a 1500 kg car traveling at 30 m/s. What is the breaking distance is needed to bring the car to a halt?" I have no idea which formula to use or...