1. J

    A Pair of Dice

    A pair of dice was thrown. What is the probability of getting 2 on the first die with any number on the second die OR getting any number on the first die with number 2 on the second die? My Attempt was Like this (1/6)(6/6) + (6/6)(1/6) = 0.3333 The book answer is 0.31. Where did I go wrong?
  2. H

    If a ball is thrown upward. . . find velocity at certain height.

    If a rock is thrown vertically upward from the surface of Mars with velocity 15 m/s, its height after t seconds is h=15t-1.86t^2. What is the velocity of the rock when its height is 25 m on its way up? On its way down? Answers: (6.24 m/sec; -6.24 m/sec) I took the height equation and...
  3. S

    A ball is thrown up at the edge of a cliff....

    A ball is thrown up at the edge of a 298 foot cliff. The ball is thrown up with an initial velocity of 72 feet per second. Its height measured in feet is given in terms of time t, measured in seconds by the equation h=-16t^2+72t+298. a. How high will the ball go and how long does it takes...
  4. J

    A fair die is thrown 20 times, find prob. that all sides appear at least once

    Hi, I have the following problem which I don't know how to solve: "A fair die is thrown 20 times. Find the probability that all of the six numbers appear at least once." I think the number of possible combinations is 6^20, but I don't know how to work out the numerator... I know 14.7 is the...
  5. E

    N dice are thrown

    I am asked N>=3 sets of dice are thrown. How many way can exactly 3 sixes turn up. I did the following for a single set of dice.... dice1+dice2=6 how many solutions? (5 choose 1)/2ceiling function??? which is 3 ways so for 3 dice to roll 6 there are... 3x3x3 then the other n-3 dice can...
  6. D

    Determine the probability that the total score is 8 when two like dice are thrown.

    ok the question in the text book goes as "Determine the probability that the total score is 8 when two like dice are thrown." im thinkin the only way to thrown total of 8 2,6 3,5 4,4 can someone help me from here?
  7. P

    Die thrown 3 times. If odd prime on first throw .....

    a man throws a die three times .if in first throw an odd prime no occurs he adds the numbers appearing in the next two draws otherwise he multiplies them.find the probability that the number thus obtained is even number i am trying to use binomial distribution is it right
  8. B

    Restricted outcomes for die thrown six times.

    Hi guys, need help with a question: An unbiased die is thrown 6 times. Calculate the probabilities that the six scores obtained will be such that a 6 occurs only on the last throw and that exactly three of the first five throws result in odd numbers.
  9. S

    Two fair dice are thrown. Prob of event A.

    Hi to all. Simple question but answer seems to be coming wrong. Question says: Two fair dice are thrown. (i) Event A is ‘the scores differ by 3 or more’. Find the probability of event A. (ii) Event B is ‘the product of the scores is greater than 8’. Find the probability of event B. When...
  10. D

    Two balls thrown and collide in mid air, produce an expression for the time between

    Hello! Basically I am stuck... been pulling my hair out trying to simplify this and come out with a simple expression! Also not sure what area of the forum to put this in, but seeing as there is nothing too complicated and its all algebra i think this is the right place. Heres the...
  11. H

    Ball thrown upwards

    A ball weighing .15kg is thrown upwards at a rate of 20m/s from a building 30m high. Neglecting air resistance, formulate a differential equation govering the ball's motion, solve it, and use the solution to determine the maximum height of the ball.
  12. Y

    a rock is thrown straight upward with an initial velocity of 50 m/s from a point 100

    a rock is thrown straight upward with an initial velocity of 50 m/s from a point 100 m above the ground. If the acceleration of the rock at any time t is a= -10 m/s^2 , what is the maximum height of the rock (in meters)? here's my attempt: a(t)= -10t take anti-derivative v(t)= -5t^2+c v(0)=...
  13. C

    Distance between Ball thrown downwards and it's starting point?

    A tennis ball is thrown down from the top of a 120m building with an initial velocity of 8m/s. What is the distance of the ball from the top of the roof 2 seconds after it was thrown? Acceleration due to gravity is 9.8m/s^2 Please don't use a physics formula to solve this question. Use...
  14. I

    Vector kinematics projectiles thrown at an angle

    Don't you have to take into consideration the fact that the projectile was launched at an angle and was above the building for a period of time before falling to the ground? If this were the case then wouldn't the 2.42 seconds be including this period which would mean that the 12 m is in fact...
  15. A

    A ball is thrown upwards

    Hey I am doing some exam questions from a mechanics textbook and I am really confused I was just wondering if anyone could help me out The question is: A ball is thrown upwards at 7ms from a point A which is 8m vertically above horizontal ground. Given that the ball moves freely under gravity...
  16. M

    Ball thrown vertically upwards

    if a ball is thrown vertically upwards with an initial speed of 20ms^-1 how do i show its maximum height and the time taken to reach this position in terms of g. Also, if the origin is now taken to be the point of projection, and the unit vector i pointing vertically upwards, what will the...
  17. S

    Thrown Ball problem

    if a ball is thrown vertically upward at 30 m/s, then its approxiamte height im meters t seconds later is given by h(t)=30t-5t^2 1) what is the domain of h? 2) for what time limit is theball more than 45 feet above the ground? 3) Whatis themaximu height of the ball? 4) After how many seconds...
  18. R

    speed while box being thrown.

    Theres a 41 kg box is thrown at a speed of 215 m/s and is brought to a halt in a collision that lasts for a time of 5.6 ms. What is the magnitude of the average net force that acts on the box during the collision? in Newtons? Anyone who can help me figure this out please.
  19. J

    A ball is thrown

    A ball is thrown stright up with the speed 25m/s how high does the ball go and at what time is it at half its height? I think am suppose to use somthing like s=v*t but i dont know how to find the time or the s so i can solve for the other. I also know gravity should play a part in the speed