Fiona is a 35-year-old woman competing in a triathlon. Her heart rate while swimming is 138 beats/minute, while cycling is 140 beats/minute, and while running is 144 beats/minute. Which of the following calculations would allow Fiona to calculate her MaxHR? MaxHR = 220+138
MaxHR = 220-35
MaxHR = 138-35
MaxHR = 144+35

the answer is b i think

area of focus

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards

there are no contact forces mentioned on the list of choices that you've provided.