Answer:
The acceleration of the player is - 4.9 m/s²
Explanation:
The given is:
1. The mass of the player is 55 kg
2. His initial speed is 4.6 m/s
3. The coefficient of the kinetic fraction between the player and the
ground is 0.50
We need to find the player acceleration
According to Newton's Law
→ ∑ forces in direction of motion = mass × acceleration
There is only the friction force opposite to the motion
→ Friction force = μR
where μ is the coefficient of friction and R is the normal reaction
→ The normal reaction R = mg
where m is the mass and g is the acceleration of gravity
→ m = 55 kg , g = 9.8 m/s²
→ R = 55 × 9.8 = 539 N
→ ∑ F = - μR
→ - μR = m × a
→ μ = 0.5 , R = 539 N , m = 55
→ -(0.5)(539) = 55 × a
→ - 269.5 = 55 a
Divide both sides by 55
→ a = - 4.9 m/s²
The acceleration of the player is - 4.9 m/s²
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Answer:
The correct option is;
(c) 64W
Explanation:
Here we have the Coefficient Of Performance, COP given by
The heat change from 23° to 6°C for a mass of 10 kg/h which is equivalent to 10/(60×60) kg/s or 2.78 g/s we have
= m·c·ΔT = 2.78 × 4.18 × (23 - 6) = 197.39 J
Therefore, plugging in the value for in the COP equation we get;
which gives
Since we were working with mass flow rate then the power input is the same as the work done per second and the power input to the refrigerator = 63.674 J/s ≈ 64 W.
The power input to the refrigerator is approximately 64 W.
Newton is a unit of force. Joules is an amount of work which is equal to the force times distance, or newton meters. So the product of newtons and meters makes joules.
So velocity=displacement/time and force=mass*acceleration. Both objects have the same acceleration because the amount of time doesn’t play a role in the equation. Momentum equation is p=mv so only the mass and overall velocity matter. Therefore, the answer is c because time is not a variable
