Answer:
the time rate of change of an object is directly proportional to the force acting on it unless an external force act on it to change it states of motion and takes the direction of the force
For the heart rate :
n = number of heat beats = 36
t = time taken to measure = 30 s = 30/60 min = 0.5 min (since 1 min = 60 sec)
R = heart rate
Heart rate is given as
inserting the values
R = 72 min⁻¹
For uncertainty :
Δn = uncertainty in number of heat beats = ± 2
Δt = uncertainty in time taken = ± 0.4 s = ± 0.4/60 min = ± 0.0067 min (since 1 min = 60 sec)
ΔR = uncertainty in heart rate
uncertainty in Heart rate is given as
inserting the values
ΔR = ± 4.96 min⁻¹