physics

posted by .

1. A 10.0 g object moving to the right at 25.0 cm/s makes an elastic head-on collision with a 15.0 g object moving in the opposite direction at 36.0 cm/s. Find the velocity of each object after the collision.

10.0 g object:

15.0g object:

2. A dentist's drill starts from rest. After 3.00 s of constant angular acceleration it turns at a rate of 2.00 multiplied by 104 rev/min.

(a) Find the drill's angular acceleration.

(b) Determine the angle (in radians) through which the drill rotates during this period.

  • physics -

    well since everything is in cm and seconds and grams we can stay in the centimeter, gram, second or"cgs" units.

    Initial momentum = 10*25 - 15*36
    = -290 (to the right is positive)
    final momentum =same = -290 = 10 U + 15 V
    elastic so initial KE = final KE
    (1/2) 10 (625) + (1/2) 15 (1296)
    3125+9720
    =12,845 dynes
    final KE =12,845 = 5 U^2 + 7.5 V^2
    so two equations, two unknowns:

    -290 = 10 U + 15 V
    12,845 = 5 U^2 + 7.5 V^2

    U = - (1.5 V + 29)
    U^2 = 2.25 V^2 + 87 V + 841

    12,845 = 5(2.25 V^2 + 87 V + 841) + 7.5 V^2

    You can solve the quadratic I think

  • physics -

    in 3 seconds from 0 to 2*10^4 revs/min
    first change rev/min to radians/sec
    2*10^4rev/min (1 min/60 s)(2 pi rad/rev)
    =2094 radians/s

    alpha = change in speed/change in time = 2094/3 = 698 radians/s^2

    angle = (1/2) alpha t^2
    =349*9 = 3141 radians

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physics

    A 10g object moving to the right at 20cm/s makes an elastic head-on collision with a 15g object moving in the opposite at 30cm/s. Find the velocity of each object after the collision. answer: -40cm/s, 10cm/s
  2. Physics

    A perfectly (non-head on) elastic collision occurs between a 0.25kg object moving east at 4m/s and a stationary 0.3kg object. Following the collision the 0.25kg object is moving at 2m/s. a) What is the speed of the 0.3kg object after …
  3. physic

    please help me.A 5.00 g object moving to the right at +20.0 cm/s makes an elastic head-on collision with a 10.0 g object that is initially at rest. (a) Find the velocity of each object after the collision. 5.00 g object 10.0 g objectt …
  4. Physics

    A 26.0 g object moving to the right at 17.0 cm/s overtakes and collides elastically with a 10.0 g object moving in the same direction at 15.0 cm/s. Find the velocity of each object after the collision. a) 26.0 g object b) 10.0 g object
  5. Physics

    A 5.00 g object moving to the right at +20.0 cm/s makes an elastic head-on collision with a 10.0 g object that is initially at rest. (a) Find the velocity of each object after the collision. 5.00 g object cm/s 10.0 g object cm/s (b) …
  6. physics

    a 10.0-g object moving to the right at 20.0 cm/s makes a elastic head-on collision with a 15-g object moving in the opposite direction at 30.0 cm/s find the velocity of each object after the collision.
  7. science

    A 2 kg object moving with a velocity of +5 m/s collides with a 4 kg object that is initially at rest. After the collision, the 2 kg object moves with a velocity of -1 m/s. (a) Find the velocity of the 4 kg object after the collision. …
  8. Physics

    A 10.0 g object moving to the right at 19.0 cm/s makes an elastic head-on collision with a 15.0 g object moving in the opposite direction at 30.0 cm/s. Find the velocity of each object after the collision.
  9. Physics

    A 5.5 kg object with a speed of 4.0 m/s collides head-on with a 13 kg object moving toward it with a speed of 3.0 m/s. The 13 kg object stops dead after the collision. (a) What is the final speed of the 5.5 kg object?
  10. Physics

    A 10 kg object (m1) initially moving to the right at 20 m/s makes a totally elastic head on collision with a 15 kg object (m2) which was initially moving to the left at 5 m/s. Find the final velocities of each object. HINT: Treat this …

More Similar Questions