Collisions A ball, mass m 1 = 2.0 kg, with an initial velocity of 2.0 m/s, strik

Question

Collisions
A ball, mass m1 = 2.0 kg, with an initial velocity of 2.0 m/s, strikes another ball, m2= 4.0 kg, initially at rest. After an elastic collision, the first ball travels at a speed of 1.0 m/s at an angle of 30

Collisions A ball, mass m1 = 2.0 kg, with an initial velocity of 2.0 m/s, strikes another ball, m2= 4.0 kg, initially at rest. After an elastic collision, the first ball travels at a speed of 1.0 m/s at an angle of 30 degree with respect to the horizontal, as shown. a. What is the momentum of the center of mass of the two-ball system before the collision? b. What are the x and y components of the final velocity v2f of the second ball? c. What is the magnitude and direction (relative to the x-axis) of the final velocity of the second ball? (Picture below) 3. Torque The figure shows an arm holding a 10 lb ball. Calculate the net torque in order to find the force that the bicep must exert to hold the ball in this position. Follow the following steps: a. Choose an appropriate center of rotation for the arm.(Hint:Use the position where the force Fbone is acting.) b. Write the net torque acting on the arm from this center of rotation. c. Set the net torque equal to zero and find the bicep force Fbicep. (Picture below)

Explanation / Answer

a) Pix = m1*v1ix + m2*v2ix = 2*2 = 4 kg m/s

Piy = m1*v1iy + m2*v2iy = 0 + 0 = 0

b) Pi = Pf

along x axis

m1*v1ix + m2*v2ix = m1*vfx + m2*v2fx

(2*2) + (4*0) = (2*1*cos30) + (4*v2fx)

v2fx = 0.567 m/s

along y axis

m1*v1iy + m2*v2iy = m1*v1fy + m2*v2fy

(2*0) + (4*0) = (2*1*sin30) + (4*v2fy)

v2fy = -0.25 m/s

c) v2f = sqrt(v1x^2 + v1y^2) = 0.619 m/s

direction = tan^-1(v1y/v1x) = 23.78 = 24 (nearly)

3)TORQUE

a) the left end

b) net torque = Fbicep*0.05 - (13.3*0.152) - (44*0.381)

c) net torque = 0

Fbicep*0.05 - (13.3*0.152) - (44*0.381) = 0

Fbicep = 375.712 N

?Fy = 0

Fbicep - Fbone - Warm - Wball = 0

Fbone = 318.412 N

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---