Answer:
Average speed of Elain = 60 km/h
Explanation:
Total Distance covered by Jack = 360km
Average Speed of Jack = 80 km/h
Time taken by Jack to complete his journey = Distance / Average speed = 360 km / 80 km/h
Time taken by Jack to complete his journey = 4.5 hours
As it is given the both Jack and Elain travelled the same amount of distance:
Total distance travelled by Elain = 360 km
It is given that Elain took 1.5 hourse more than Jack to cover the distance, so Time taken by Elain to cover the distance is = 4.5 hours + 1.5 hours = 6 hours
Average speed of Elain = Distance/ time = 360 km / 6 hours
Average speed of Elain = 60 km/h
The cart experiences a frictional force which is directly proportional to its weight. This means that there must be a force applied on the car to balance the forces on the car to produce a net force of 0.
This is in accordance to Newton's first law which states that an object at rest will remain at rest and an object in motion will remain in motion unless an external force acts on it. The force must be a resultant force.
Therefore, the force needed increases with the total weight of the cart as well as with the added mass in a linear manner.
Answer:
doppler effect
Explanation:
When the relative motion of two bodies results in the wavelength becoming shorter this means that the bodies are getting closer. This is known as blue shift.
When the relative motion of two bodies results in the wavelength becoming longer this means that the bodies are getting farther. This is known as red shift.
Collectively this phenomenon is known as the Doppler effect.
It can never be shorter than a component - magnitude of avector is the square root of the sum of the components squared, and a square function never produces a negative number. However, it can be the same size as its component, if that component is the only one
Answer:
the magnitude of the velocity of the block just after impact is 2.598 m/s and the original speed of the bullect is 324.76m/s.
Explanation:
a) Kinetic energy of block = potential energy in spring
½ mv² = ½ kx²
Here m stands for combined mass (block + bullet),
which is just 1 kg. Spring constant k is unknown, but you can find it from given data:
k = 0.75 N / 0.25 cm
= 3 N/cm, or 300 N/m.
From the energy equation above, solve for v,
v = v √(k/m)
= 0.15 √(300/1)
= 2.598 m/s.
b) Momentum before impact = momentum after impact.
Since m = 1 kg,
v = 2.598 m/s,
p = 2.598 kg m/s.
This is the same momentum carried by bullet as it strikes the block. Therefore, if u is bullet speed,
u = 2.598 kg m/s / 8 × 10⁻³ kg
= 324.76 m/s.
Hence, the magnitude of the velocity of the block just after impact is 2.598 m/s and the original speed of the bullect is 324.76m/s.
