Answer:
382.74 kJ.
Explanation:
The work that must be done to stop an 1100 kg car travelling at 59 km/h is - 382.74 kJ.
Answer:

Explanation:
The motion of the skater is a uniformly accelerated motion, so we can find the deceleration by using the following suvat equation:

where
v is the final velocity
u is the initial velocity
a is the acceleration
s is the displacement
In this problem, we have:
u = 19 m/s is the initial velocity of the skater
v = 18 m/s is the final velocity of the skater
s = 2.0 m is the displacement
Solving for a, we can find the acceleration:

And the negative sign tells us that the acceleration is in the opposite direction to the motion (so, it is a deceleration)
Explanation:
power=f×v. recall= distances/ time
= f× d/t
= 30 × 2/5
=12watt
Answer:
19320 kg/m³
Explanation:
density: This can be defined as the ratio of the mass of a body to its volume. The S.I unit of Density is kg/m³.
The formula of density is given as,
D = m/v ......................... Equation 1.
Where D = Density of the gold, m = mass of the gold, v = volume of the gold.
Note: From Archimedes's Principle, the piece of gold displace an amount of water that is equal to it's volume.
Amount of water displace = 27.2 - 25 = 2.2 mL.
Given: m = 42.504 g = 0.042504 kg, v = 2.2 mL = (2.2/10⁶) m³ = 0.0000022 m³
Substitute into equation 1
D = 0.042504/0.0000022
D = 19320 kg/m³
Hence the density of the piece of gold = 19320 kg/m³