Answer:
Their efforts would be expressed in units of Joules per second
Explanation:
The unit of their efforts can be derived from the formula of power which is given by the product of mass, acceleration and distance (the product is energy with unit joules) divided by time taken to complete the task (unit is seconds)
Therefore, the unit of their efforts would be joules per second
Speed is equal to distance traveled divided by the time. So it's 3.5 m/s
Frequency = (speed) / (wavelength)
Speed = 3 x 10⁸ m/s
Wavelength = 3 cm = 0.03 m
Frequency = (3 x 10⁸ m/s) / (0.03 m)
Frequency = (3 x 10⁸ / 0.03) (m / m-s)
Frequency = 1 x 10¹⁰ Hz (10 Gigahertz)
Answer:
Force = 35 N
Explanation:
From Newton's third law of motion, the boy must apply a force greater than the weight of the sled to lift it.
weight of sled = mg
where m is its mass and g the force of gravity on it.
weight of sled = 50 N
Force applied by the boy on the sled = 15 N
Since the force applied on the sled by the boy is lesser than the weight of the sled, then;
Force that the sled exerts on the student = 50 - 15
= 35 N
The force exerted by the sled on the student is 35 N.
