Answer:

Explanation:
Total =40 miles.
y miles at x miles/hr.
40- y miles at 1.25 x miles/hr.\
We know that
Distance = time x velocity
For y miles
Lets time taken to cover y miles is t
y = x t
t=y/x -----------1
For 40- y
Lets time taken to cover 40- y is t'
40- y = 1.25 x t'
t'=(40-y)/1.25x -----------2
By adding both equation
t+t'=y/x + (40-y)/1.25x
t+t'=(32+0.2y)/x
Now lets time T taken by Marla if she will travel at x miles per hr for entire trip.
40 = x T
T=40/x
So

To find numerical value of above expression we have to know the value of y.
Answer: 
Explanation:
Given
If an object reaches the topmost point i.e. it cannot travel beyond that point as its velocity is zero at the topmost point
As some velocity is needed to move the object, so velocity at topmost point is zero
The centripetal acceleration = 236.63 m/s²
The force = 17.98 N
<h3>Further explanation</h3>
Given
mass = 76 g = 0.076 kg
r = 1.5 m
f = 2 rps = 2 rotation per second
Required
The centripetal acceleration
The Force tension
Solution
Centripetal force is a force acting on objects that move in a circle in the direction toward the center of the circle

F = centripetal force, N
m = mass, Kg
v = linear velocity, m / s
r = radius, m
The speed that is in the direction of the circle is called linear velocity
Can be formulated:

r = circle radius
f = rotation per second (RPS)
The linear velocity : 2 x 3.14 x 1.5 x 2 =18.84 m/s
The centripetal acceleration : ac = v²/R = 236.63 m/s²
The force : F = m x ac = 0.076 x 236.63 = 17.98 N
Answer: will be raised through lower temperature change(lower ∆T) when compared to the low heat capacity substance.
Explanation:
Heat capacity is the amount of heat needed to raise the temperature of a substance through 1°C(1 unit temperature).
Therefore the high heat capacity substance will require more heat to raise it through 1 unit temperature when compared to the low heat capacity substance. So when the same amount of heat is added to the two substance the high heat capacity substance is raised through lower temperature change when compared to the low heat capacity substance.