Krista and Blaire are identical twins that were separated at birth. Both of the girls are scared of thunder when they are young. Krista's adoptive parents teach her to deal with her fear by pretending that the thunder is a big drum in an orchestra. Blaire's adoptive parents, on the other hand, teach her to deal with her fear of thunder by thinking about sunny days ahead.Both girls have inherited a fear of thunder. The difference in their way of dealing with this fear, however, can best be explained by differences in their _______.

Answer:

a) = -30 m/s

b) = 30 m/s

Explanation:

a)

Consider the car A travel at a velocity of = 90 km/h and the car B travel at the velocity of = 120 km/h. As the velocity of the car B is greater than the car A, So it cross the car A.  Consider The velocity of car A relative to car B is and it is equal to the velocity of car A minus the velocity of car B.

= -

= 90 - 120

= -30 m/s

b)

Consider The velocity of car B relative to car A is and it is equal to the velocity of car B minus the velocity of car A.

= -

= 120 - 90

= 30 m/s

Answer: 94.9 metres

Explanation:

Given that,

Force between the two charges (F) = 24x10² N

Negative charge (q1) = 8x10-5C

Positive charge (q2) = 3x10C

Distance between charges (r) = ?

Apply the formula for

F= (kq1q2) / r²

Recall that k is Coulomb's constant with a value of 9 × 10^9 Nm2C−2

Then,

24x10² N = (9 × 10^9 Nm2C−2 x 8x10-5C x 3x10C) / r²

24x10² N = (2.16 x 10^7) / r²

r² = (2.16 x 10^7 / 24x10² N)

r² = 9000

To get the value of r, find the square root

r = √9000

r = 94.868m (rounded to the nearest tenth as 94.9m)

Thus, a distance of 94.9 metres separates the charges.

Answer: The entangled players would move with a speed of 0.2 m/s in the direction direction of the motion of second soccer player.

Explanation:

From law of conservation of momentum,

Initial momentum of the closed system  = final momentum of the closed system

Since, no external force is acting on the players, total momentum would be conserved.

m₁u₁+m₂u₂=(m₁+m₂)v

where, m₁ is the mass of one soccer player = 40 kg

u₁ is its initial velocity before collision = 4 m/s

m₂ is the mass of the other soccer player = 60 kg

u₂ is the initial velocity before collision = - 3 m/s (∵opposite direction)

After collision, the two players get entangled and hence move with the same final velocity v.

40 kg × 4 m/s - 60 kg × 3 m/s = (40 kg + 60 kg ) v

160  kg m/s - 180 kg m/s = 100 kg v

v = -0.2 m/s

Hence, the entangled players would move with a speed of 0.2 m/s in the direction direction of the motion of second soccer player.