Answer:
t₂ = 3.89 s
Explanation:
given,
speed of car = 23 m/s
speed of motorcycle = 23 m/s
after time of 4 s distance between them is equal to = 53 m
motorcycle accelerates at = 7 m/s
time taken to catch up with car = ?
let t₂ be the time in which motorcycle catches car.
distance traveled by car in t₂ s
d = 23 t₂ + 53
distance traveled by motorcycle
using equation of motion


now, equating both the distances


t₂ = 3.89 s
time taken by the motorcycle to catch the car is equal to 3.89 s
The frequency of this wave is 3
Answer:
t=0.42s
Explanation:
Here you have an inelastic collision. By the conservation of the momentum you have:

m1: mass of the bullet
m2: wooden block mass
v1: velocity of the bullet
v2: velocity of the wooden block
v: velocity of bullet and wooden block after the collision.
By noticing that after the collision, both objects reach the same height from where the wooden block was dropped, you can assume that v is equal to the negative of v2. In other words:

Where you assumed that the negative direction is upward. By replacing and doing v2 the subject of the formula you get:

Now, with this information you can use the equation for the final speed of an accelerated motion and doing t the subject of the formula. IN other words:

hence, the time is t=0.42 s
Answer: The correct answer is Image B.
Explanation: For an object to accelerate, there should be unbalanced forces present. An object will move in the direction of net force.
Balanced forces are defined as the forces acting on the same object which are equal in magnitude but act in opposite direction. The net forces are 0.
Unbalanced forces are defined as the forces acting on the same object which are unequal in magnitude. The net force is non-zero.
For the given images:
Image A: This box will accelerate easily because the net force is non-zero and is moving in right direction.
Image B: This box will not accelerate because the net force is zero as all the forces are balancing one another. Hence, the object will stay at rest.
Image C: This box will accelerate easily because the net force is non-zero and is acting in between the normal and applied force.
Image D: This box will accelerate easily because the net force is non-zero and is moving in right direction.
Hence, the correct option is Image B.