The Berlin marathon is one of the fastest marathons courses; many world records have been set there. In 2014 Dennis Kimetto ran
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Answer: 20.21 kg
Explanation:
The mass hanging from the pulley is pulling the cart. The force by which cart is being pulled is equal to weight of the hanging mass.
⇒F=0.200 kg ×9.8 m/s²=1.96 N
Since there is no other force acting on the cart and there is no friction, so this force will pull the cart.
The Cart covers 1.12 m distance in 4.8 s.
From the equation of motion,
s = u t + 0.5 × a t²
We will find the acceleration of the cart,
Distance covered, s = 1.12 m
Initial velocity, u = 0 ( staring from rest)
Time taken, t = 4.8 s
⇒1.12 m = 0 + 0.5 × a × (4.8 s)²
⇒a = 0.097 m/s²
Now the force which causes this acceleration is:
F = ma
where m is the mass of the cart and a is the acceleration of the cart
⇒1.96 N = m×0.097 m/s²
⇒m = 20.21 kg
Hence, the mass of the cart is 20.21 kg.