Answer:
a. 150 N
Explanation:
Gravitational Force: This is the force that act on a body under gravity.
The gravitational force always attract every object on or near the earth's surface. The earth therefore, exerts an attractive force on every object on or near it.
The S.I unit of gravitational force is Newton(N).
Mathematically, gravitational force of attraction is expressed as
(i) F = GmM/r² ........................ Equation 1 ( when it involves two object of different masses on the earth)
(ii) F = mg ............................... Equation 2 ( when it involves one mass and the gravitational field).
Given: m = 17 kg, g = 8.8 m/s²
Substituting into equation 2,
F = 17(8.8)
F = 149.6 N
F ≈ 150 N.
Thus the gravitational force = 150 N
The correct option is a. 150 N
Answer:
1.67m/s
Explanation:
Total Distance to be travelled by a Runner=100m
Time Taken=10*6s
Speed=Distance/Time
=100/10*6=10/6=1.67m/s
When air resistance<span> acts, acceleration during a fall </span>will<span> be less than g because </span>air resistance affects<span> the motion of the falling </span>objects<span> by slowing it down. </span>Air resistance<span> depends on two important factors - the</span>speed<span> of the </span>object<span> and its surface area. Increasing the surface area of an </span>object<span> decreases its </span>speed<span>.</span>
Answer: When a lightning bolt travels from the cloud to the ground it actually opens up a little hole in the air, called a channel. Once then light is gone the air collapses back in and creates a sound wave that we hear as thunder. The reason we see lightning before we hear thunder is because light travels faster than sound!
Explanation:
The efficiency of a machine indicates how well its input energy is converted to useful output energy or work. It is a major factor in the usefulness of a machine and is the fraction or percentage of the output divided by the input.
According to the Law of Conservation of Energy, the total output energy or work must equal the total input energy. However, some of the input energy does not contribute to the output work and is lost to such things as friction and heat.
Examples of machine efficiency include a lever, automobile, and perpetual motion machine.
