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    physics help?

    1 AnswerPhysics3 months ago
  • physics help pls?

    1) The energy released in nuclear reactions is released as *blank*

    2)In the proton-proton process, four hydrogen nuclei are used to produce one helium nucleus. This process releases energy because the mass of the helium nucleus is ___________ the mass of the hydrogen nuclei.

    3)What do you need to do to start a fusion reaction?

       a)bombard the unstable nuclei with neutrons

       b)place the nuclei under intense heat and pressure

       c)both nuclear bombardment and intense heat and pressure

       d)neither nuclear bombardment nor intense heat and pressure

    4)Nuclear power plants used for electricity generation are powered by ______ reactors.

    5)What is the energy equivalent of the mass of an electron (9.1 x 10-31 kg)?

    1 AnswerPhysics3 months ago
  • PHYSICS!!! help?

    1) If a Polonium-211 nucleus decays by alpha decay, what is the daughter nucleus?

    2)If Actinium-227 decays by beta decay, what is the daughter nucleus?

    3)If you have 120 atoms of a radioactive material with a half-life of 50 s, how many of the original atoms will you still have after 100 s?

    4)Ionization smoke detectors contain small amount of a radioactive source. Which would be a better choice of source if you wanted to make a detector with a “lifetime guarantee” that would produce a fairly constant signal over a person's lifetime?

    a)1 g of a material with a half-life of 400 years

    b)10 g of a material with a half-life of 40 years

    c)both would be equally effective

    d)neither would be effective

    1 AnswerPhysics3 months ago
  • PHYSICS PLS HELP!!!?

    1) If 100 g of water at 80oC is added to a 100 g steel cup at 20oC, the magnitude of the change in temperature of the water will be ____________ the magnitude of the change in temperature of the cup.

    2)How much energy would need to be input to 10.0 kg of ice to turn it to water at 0.0oC, given a latent heat of fusion of 3.3 x 105 J/kg?

    3)A solid copper ball with a mass of 1.0 kg and a temperature of 30°C is placed on a sheet of ice at 0°C. If 1.0 kg of water at the same temperature were poured on the ice, the water would melt _____ ice.

    1 AnswerPhysics3 months ago
  • PHYSICS PLEASE HELP ?

    One block of ice slides down the (frictionless) ramp while the other falls off the end. Which block is traveling faster when it reaches the ground?

    A 20.0 kg child sits at the top of a playground slide 2.0 m above the ground. Assuming very little friction on the slide, what is the child’s speed when she lands on the ground after sliding down the slide?

    A machine with a 4 W motor does 20 J of useful work in 10 s. What is the machine's efficiency?

    A 12 W motor is used to lift a 1.0 N object a vertical distance of 6.0 m in 2.0 s. What is the efficiency of the system?

    A 1 kg model roller coaster car starts from rest at a height of 5 m. The second hill on the track has a height of 3 m. Neglecting friction, what would you expect for the speed of the car at the top of the second hill?

    A 1 kg model roller coaster car starts from rest at a height of 5 m. The second hill on the track has a height of 3 m. If it comes to rest at the top of the second hill, what is the efficiency of the roller coaster?

    A 100 kg roller coaster car starts from rest at a height of 140 m. The second hill on the track has a height of 95 m. If it comes to rest at the top of the second hill, what is the work done by friction on the roller coaster car?

    2 AnswersPhysics3 months ago
  • PHYSICS HELP!?

    At a bowling alley, a ball-feeder mechanism must exert a force to push the bowling balls up a 1.0-m long ramp. The ramp leads the balls to a chute 0.50 m above the base of the ramp. Approximately how much force must be exerted on a 5.0-kg bowling ball?

    2 AnswersPhysics3 months ago
  • physics plz help?

    When you walk up a flight of stairs at constant speed, you are increasing your ________ energy.

    a) gravitational potential 

    b)kinetic

    c)gravitational potential and kinetic 

    d)u r not increasing both gravitaional and kinetic 

    3 AnswersPhysics3 months ago
  • physics help plz?

    If a 70 kg person climbs a 3 m flight of stairs at constant speed, their work done while climbing is:

    3 AnswersPhysics3 months ago
  • physics helppp?

    If a 65 kg person accelerates uniformly from a standing start to a sprint in 2.7 s over 10.0 m, what was their work done while accelerating?

    3 AnswersPhysics3 months ago
  • physics plz?

    A car is going 10 kph. The driver hits the brakes and the car travels 1 m after the brakes are applied. A while later the same car is going 20 kph. The driver hits the brakes. About how far does the car go after the brakes are applied?

    1 AnswerPhysics3 months ago
  • PHYSICS HELP?

     A box of mass 12 kg is at rest on a horizontal surface. What is the magnitude and direction of the gravitational and normal forces acting on the box?(b) Another box of mass 12 kg is also at rest on a horizontal surface, but a student is pushing downward on this box with a force of magnitude 25 N. What is the magnitude and direction of the gravitational and normal forces acting on this 12 kg box?

    3 AnswersPhysics4 months ago
  • physics help?

    An astronaut drops a camera from rest while exiting a spacecraft on the Moon. The camera falls 2.3 m in 1.7 s. Calculate (a) the acceleration due to gravity on the Moon and (b) the impact velocity of the camera with the surface

    4 AnswersPhysics4 months ago
  • physics pls help?

    Consider a situation in which you are driving at 75 km/h when you notice a stalled vehicle 48 m directly ahead of you. Your brakes can apply a constant acceleration of 4.8 m/s2 [opposite the direction of motion]. (a) What is the distance you will travel while braking? (b) To avoid a collision, how much time do you have, after noticing the stalled vehicle, to hit the brakes

    3 AnswersPhysics4 months ago
  • he maximum acceleration of blood in the aorta can be used to test the ventricular ?

    function. The period during which maximum acceleration of the blood in the aorta occurs is during the first portion of the left ventricle's pumping action. During this period, the acceleration is essentially constant. Doppler echocardiography uses ultrasound to measure blood speeds in the aorta. The results for one patient show that the blood in the aorta begins at a speed of 0.10 m/s and undergoes constant acceleration for 38 ms, reaching a peak speed of 1.29 m/s. (a) What is the magnitude of the acceleration over this time interval? (b) How far does blood travel during this period?

    1 AnswerPhysics4 months ago
  • Objects accelerate at 9.8 m/s2 [down] when falling?

     (a) How long does it take an object dropped from rest (from the top of a tall building) to reach a velocity of 15 m/s [down]? (b) How far does the object fall during that time?

    1 AnswerPhysics4 months ago
  • Objects accelerate at 9.8 m/s2 [down] when falling?

     (a) How long does it take an object dropped from rest (from the top of a tall building) to reach a velocity of 15 m/s [down]? (b) How far does the object fall during that time?

    1 AnswerPhysics4 months ago
  • to avoid getting caught speeding, what is the maximum speed at which you should complete your ?

    trip if you realize 10 km into your 20 km route that you have been traveling at 125 km/h when the speed limit is 100 km/h? (Hint: the answer is not 75 km/h.) Illustrate your solution with a graph

    3 AnswersPhysics4 months ago