The angle between $$\mathrm{A}=\hat{\mathbf{i}}+\hat{\mathbf{j}}$$ and $$\mathrm{B}=\hat{\mathbf{i}}-\hat{\mathbf{j}}$$ is:
1. $$45^{\circ}$$
2. $$90^{\circ}$$
3. $$-45^{\circ}$$
4. $$180^{\circ}$$
Subtopic: Â Scalar Product |
Â 78%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

If a vector $$2\hat{i}+3\hat{j}+8\hat{k}$$ is perpendicular to the vector $$-4\hat{i}+4\hat{j}+\alpha \hat{k},$$ then the value of $$\alpha$$ will be:$\mathrm{}$
1. $-1$
2. $-\frac{1}{2}$
3. $\frac{1}{2}$
4. $$1$$

Subtopic: Â Scalar Product |
Â 60%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints

A block of $$1$$ kg is released from a top of a smooth curve AB, and then it encounters a rough surface BC, coming to rest at C. The work done by friction is: ($$g=10$$ m/s2)

1. $$25$$ J
2. $$50$$ J
3. $$-25$$ J
4. $$-50$$ J

Subtopic: Â Work Energy Theorem |
Â 69%
From NCERT
Hints

The work done by all the forces (external and internal) on a system equals the change in:

 1 total energy 2 kinetic energy 3 potential energy 4 none of these
Subtopic: Â Work Energy Theorem |
Â 73%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A bullet from a gun is fired on a rectangular wooden block with velocity $$u$$. When bullet travels $$24$$ cm through the block along its length horizontally, velocity of bullet becomes $$u/3$$. Then it further penetrates into the block in the same direction before coming to rest exactly at the other end of the block. The total length of the block is:
1. $$30$$ cm
2. $$27$$ cm
3. $$24$$ cm
4. $$28$$ cm
Subtopic: Â Work Energy Theorem |
Â 67%
From NCERT
NEET - 2023
Hints

A body of mass $$1$$ kg is thrown upwards with a velocity $$20$$ ms-1. It momentarily comes to rest after attaining a height of $$18$$ m. How much energy is lost due to air friction?
(Take $$g=10$$ ms-2)
1. $$20$$ J
2. $$30$$ J
3. $$40$$ J
4. $$10$$ J

Subtopic: Â Work Energy Theorem |
Â 87%
From NCERT
AIPMT - 2009
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A bicyclist comes to a skidding stop in $$10$$ m. During this process, the force on the bicycle due to the road is $$200$$ N is directly opposed to the motion. The work done by the cycle on the road is:
1. $$+2000$$ J
2. $$-200$$ J
3. zero
4. $$-20000$$ J

Subtopic: Â Work done by constant force |
Â 58%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

The work done by gravity on a projectile of mass $$m$$ fired with a speed $$u$$ at an angle $$\theta$$ to the horizontal, until the time of impact is:

 1 zero 2 $$-\frac12mu^2cos^2\theta$$ 3 $$-\frac12mu^2sin^2\theta$$ 4 $$-\frac12mu^2$$
Subtopic: Â Work done by constant force |
Â 59%
From NCERT
Hints

A force of $$100$$ N acts on a block, always acting opposite to its velocity. The block moves from $$x=4$$ m to $$x=10$$ m and then to $$x=6$$ m. The work done by the force is:
1.  $$200$$ J
2.  $$-200$$ J
3.  $$1000$$ J
4.  $$-1000$$ J
Subtopic: Â Work done by constant force |
From NCERT
Hints

A body of mass $$0.5$$ kg travels in a straight line with velocity $$v=ax^{3/2}$$ where $$a=5~\mathrm{m^{-1/2}s^{-1}}$$. The work done by the net force during its displacement from $$x=0$$ m to $$x=2$$ m is:
1. $$15$$ J
2. $$50$$ J
3. $$10$$ J
4. $$100$$ J

Subtopic: Â Work Done by Variable Force |
Â 66%
From NCERT
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh