In: Physics

((8.27)Q:7)

Two ice skaters, Daniel (mass 70.0 kg ) and Rebecca (mass 45.0 kg ), are practicing. Daniel stops to tie his shoelace and, while at rest, is struck by Rebecca, who is moving at 14.0 m/s before she collides with him. After the collision, Rebecca has a velocity of magnitude 8.00 m/s at an angle of 55.1 ∘ from her initial direction. Both skaters move on the frictionless, horizontal surface of the rink.

A) What is the magnitude of Daniel's velocity after the collision?

B) What is the direction of Daniel's velocity after the collision?

C) What is the change in total kinetic energy of the two skaters as a result of the collision?

**Let initially rebecca is moving in +x
direction.**

**before collsion,**

**m1 = 45 kg(Rebecca), u1 = 14 m/s**

**m2 = 70 kg(Daniel), u2 = 0**

**after the collsion,**

**v1 = 8 m/s at 55.1 degrees**

**v2 = ?**

**let theta is the angle made by Daniel with +x
axis**

**a) Apply conservation of moemntum in
x-direction**

**m1*u1x + m2*u2x = m1*v1x + m2*v2x**

**45*14 + 0 = 45*8*cos(55.1) + 70*v2x**

**v2x = (45*14 - 45*8*cos(55.1) )/70**

**= 6.06 m/s**

**Apply conservation of moemntum in
y-direction**

**m1*u1y + m2*u2y = m1*v1y + m2*v2y**

**0 + 0 = 45*8*sin(55.1) + 70*v2x**

**v2y = - 45*8*sin(55.1)/70**

**= - 4.22 m/s**

**V2 = sqrt(v2x^2 + v2y^2)**

**= sqrt(6.06^2 + 4.22^2)**

**= 7.38 m/s
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<------------Answer**

**b)
Direction : theta = tan^-1(v2y/v2x)**

**= tan^-1(4.22/6.06)**

**= 34.8 degrees
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<------------Answer**

**c) delta_KE = 0.5*m1*u1^2 - (0.5*m1*v1^2 +
0.5*m2*v2^2)**

**= 0.5*55*14^2 - (0.5*45*8^2 +
0.5*70*7.38^2)**

**= 2044 J
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<------------Answer**

Two ice skaters, Daniel (mass = 65.0 kg) and Rebecca (mass =
45.0 kg) are practicing on the ice. Daniel stops to tie his lace,
and while at rest he is struck by Rebecca, who is moving 12.0 m/s
before she collides with him. After the collision, Rebecca is
moving forward at 8.50 m/s at a 53 degree angle with respect to her
initial direction. What is the velocity vector (magnitude and
direction, or x- and y-components) of Daniel after...

Daniel with mass 65.0 kg and Rebecca with mass 45.0 kg are
skating. While Daniel stands at rest, He is struck by Rebecca. She
is moving at 13.0 m/s before she collides with him. Rebecca has a
velocity of magnitude 6.00 m/s at an angle of 55.1 ∘ from her
initial direction after the collision. Both skaters move on the
frictionless and horizontal surface .
a)Find the magnitude of Daniel's velocity after the
collision?
b)Find the direction of Daniel's velocity...

Mahmut with mass 70.0 kg and Güllü with mass 45.0 kg are
skating. While Mahmut stands at rest, He is struck by Güllü. She is
moving at 15.0 m/s before she collides with him. Güllü has a
velocity of magnitude 10.00 m/s at an angle of 55.0 ∘ from her
initial direction after the collision. Both skaters move on the
frictionless and horizontal surface .
a)Find the magnitude of Mahmut's velocity after the
collision?
b)Find the direction of Mahmut's velocity...

Friction between the skaters and the ice is negligible.
Ann has a mass of M, a moment of inertia of
3Ioand has a velocity of va = -2voi
+ 7voj. She is spinning with an angular velocity
10ωo up.
Bob has a mass of 2M, a moment of inertia of
5Io and has a velocity of vb = 4voi + voj. He is spinning with
an angular velocity 2ωo down.
The two ice dancers join together (collide) and hold onto...

A 70.0 kg70.0 kg ice hockey goalie, originally at rest, has a
0.280 kg0.280 kg hockey puck slapped at him at a velocity of 33.5
m/s.33.5 m/s. Suppose the goalie and the puck have an elastic
collision, and the puck is reflected back in the direction from
which it came. What would the final velocities ?goalievgoalie and
?puckvpuck of the goalie and the puck, respectively, be in this
case? Assume that the collision is completely elastic.
?goalie=vgoalie=
m/sm/s
?puck=vpuck=
m/sm/s...

Two ice skaters are gliding together along the ice, both moving
at the same, constant velocity. They are sliding without exerting a
force meaning you can neglect any friction.
The first skater (the one in the back) as a mass M 1.
The second skater (the one in front) has a mass M 2.
As they are sliding with an initial speed v i, the first skater
pushes the second skater directly forward in the direction they are
moving. After...

A 70.0-kg ice hockey goalie, originally at rest, has a 0.170-kg
hockey puck slapped at him at a velocity of 43.5 m/s. Suppose the
goalie and the puck have an elastic collision, and the puck is
reflected back in the direction from which it came. What would the
final velocities of the goalie and the puck be in this case? Assume
that the collision is completely elastic.

Two skaters at rest, one of 120 kg and the second of 60 kg, push
off against another. Which will gain the largest magnitude of
momentum? A. Both skaters will gain momentum of the same magnitude
B. Neither skaters will gain any momentum C. the 120-kg skater D.
the 60-kg skater E. the momentum of each skater is conserved
Momentum changes for each of these scenarios except for A. a
neutron in a nuclear reactor that changes the direction but...

1. Two forces P and Q act on
an object of mass 20.0 kg with Q being the larger
of the two forces. When both forces are directed to the left, the
magnitude of the acceleration of the object is 0.900
m/s2. However, when the force P is
directed to the left and the force Q is directed
to the right, the object has an acceleration of 0.400
m/s2 to the right. Find the magnitudes of the two
forces
P...

Two friends, Al and Jo, have a combined mass of 166 kg. At the
ice skating rink, they stand close together on skates, at rest and
facing each other. Using their arms, they push on each other for 1
second and move off in opposite directions. Al moves off with a
speed of 5.9 m/sec in one direction and Jo moves off with a speed
of 9.7 m/sec in the other. You can assume friction is
negligible.
1)What is Al's...

ADVERTISEMENT

ADVERTISEMENT

Latest Questions

- If you deposit money today in an account that pays 13% annual interest, how long will...
- Taylor’s “Libertarianism”
- Given a system with 4M bytes of address space per process, 64M bytes of physical memory,...
- Explain in your own words the requirements an indeterminate structure should satisfy and name the methods...
- Let P2 be the vector space of all polynomials of degree less than or equal to...
- Develop a python program to create a quiz with limited time and attempts!!! Add comments and...
- Quantitative noninvasive techniques are needed for routinely assessing symptoms of peripheral neuropathies, such as carpal tunnel...

ADVERTISEMENT